Customizing citations and the list of publications depending on the author

Question

Say I use a bibliography file in my document, relying on Biblatex and Biber for citation management.

Given a citation command such as \cite{A, B, C} (or any other standard Biblatex citation command), I'd like the resulting citations to be typeset differently depending on whether a given field (e.g. the author field) in the corresponding bibliography entry contains a given string (e.g. someone's lastname).

Besides, I'd like to generate two different bibliography sections in the resulting document, depending on the same condition as above.

Typically this would be used to differentiate, both at the citation level in the main text and in the appendix, the publications that I co-authored from others.

EDIT: adding a MWE:

\documentclass{article}
\usepackage{filecontents}
\usepackage[backend=biber,style = alphabetic]{biblatex}
\usepackage[colorlinks=true, breaklinks, allcolors = blue]{hyperref}
\DeclareSourcemap{%
  \maps[datatype=bibtex]{%
    \map{%
      \step[fieldsource=author, match=Doe, final]%
      \step[fieldset=keywords, fieldvalue=doe]%
    }%
  }%
}
\begin{filecontents}{\jobname.bib}
@Book{p1,
  author =       "A. U. Thor and John Doe",
  title =        "A Scientific Article 1",
  year =         "1975"  
}
@Book{p2,
  author =       "John Doe",
  title =        "A Scientific Article 2",
  year =         "1985"  
}
@Book{p3,
  author =       "Joe Bar",
  title =        "A Scientific Article 3",
  year =         "1995"  
}
@Book{p4,
  author =       "Jane Baz",
  title =        "A Scientific Article 4",
  year =         "2005"  
}
\end{filecontents}
\addbibresource{\jobname.bib}
\begin{document}
% Requirement 1: should make citations of Doe bold
In \parencite{p4, p1, p2, p3}, ``TD75'' and ``Doe85'' should appear in
bold (the semicolon should remain plain).

% Requirement 2: separating bibliographies. IT WORKS.
\section{Co-authored Publications}
\nocite{*}
\printbibliography[keyword=doe,heading=none]

\section{Other Publications}
\nocite{*}
\printbibliography[notkeyword=doe,heading=none] 
\end{document}

Answer 1

With the solution from biblatex: separating publications of a specific author in the bibliography that sets the keywords you only need

\DeclareFieldFormat{prefixnumber}{\ifkeyword{doe}{\mkbibbold{#1}}{#1}}
\DeclareFieldFormat{labelalpha}{\ifkeyword{doe}{\mkbibbold{#1}}{#1}}
\DeclareFieldFormat{extraalpha}{\ifkeyword{doe}{\mkbibbold{#1}}{#1}}

to get what you want.

MWE

\documentclass{article}
\usepackage{filecontents}
\usepackage[backend=biber,style = alphabetic]{biblatex}
\usepackage[colorlinks=true, breaklinks, allcolors = blue]{hyperref}
\DeclareSourcemap{%
  \maps[datatype=bibtex]{%
    \map{%
      \step[fieldsource=author, match=Doe, final]%
      \step[fieldset=keywords, fieldvalue=doe]%
    }%
  }%
}
\begin{filecontents}{\jobname.bib}
@Book{p1,
  author =       "A. U. Thor and John Doe",
  title =        "A Scientific Article 1",
  year =         "1975"  
}
@Book{p2,
  author =       "John Doe",
  title =        "A Scientific Article 2",
  year =         "1985"  
}
@Book{p3,
  author =       "Joe Bar",
  title =        "A Scientific Article 3",
  year =         "1995"  
}
@Book{p4,
  author =       "Jane Baz",
  title =        "A Scientific Article 4",
  year =         "2005"  
}
\end{filecontents}
\addbibresource{\jobname.bib}

\DeclareFieldFormat{prefixnumber}{\ifkeyword{doe}{\mkbibbold{#1}}{#1}}
\DeclareFieldFormat{labelalpha}{\ifkeyword{doe}{\mkbibbold{#1}}{#1}}
\DeclareFieldFormat{extraalpha}{\ifkeyword{doe}{\mkbibbold{#1}}{#1}}

\nocite{*}
\begin{document}
In \parencite{p4, p1, p2, p3}, ``TD75'' and ``Doe85'' should appear in
bold (the semicolon should remain plain).

\section{Co-authored Publications}
\printbibliography[keyword=doe,heading=none]

\section{Other Publications}
\printbibliography[notkeyword=doe,heading=none] 
\end{document}

---

Just because it is fancy to use name hashes, here is a version of Audrey's answer to biblatex: filter out publications from a specific author in the references dynamically.

You can find the name hash you need to use in the .bbl file (as described in more detail in Highlight an author in bibliography using biblatex allowing bibliography style to format it).

This solution uses categories instead of keywords so we have to adjust the code a bit, but the basic idea is the same.

\documentclass{article}
\usepackage{filecontents}
\usepackage[backend=biber,style = alphabetic]{biblatex}
\usepackage[colorlinks=true, breaklinks, allcolors = blue]{hyperref}
\begin{filecontents}{\jobname.bib}
@Book{p1,
  author =       "A. U. Thor and John Doe",
  title =        "A Scientific Article 1",
  year =         "1975"  
}
@Book{p2,
  author =       "John Doe",
  title =        "A Scientific Article 2",
  year =         "1985"  
}
@Book{p3,
  author =       "Joe Bar",
  title =        "A Scientific Article 3",
  year =         "1995"  
}
@Book{p4,
  author =       "Jane Baz",
  title =        "A Scientific Article 4",
  year =         "2005"  
}
\end{filecontents}
\addbibresource{\jobname.bib}

\DeclareBibliographyCategory{byname}

\DeclareIndexNameFormat{byname}{%
  \iffieldequalstr{hash}{bd051a2f7a5f377e3a62581b0e0f8577}
    {\addtocategory{byname}{\thefield{entrykey}}}
    {}%
}

\AtDataInput{%
  \indexnames[byname]{author}}


\DeclareFieldFormat{prefixnumber}{\ifcategory{byname}{\mkbibbold{#1}}{#1}}
\DeclareFieldFormat{labelalpha}{\ifcategory{byname}{\mkbibbold{#1}}{#1}}
\DeclareFieldFormat{extraalpha}{\ifcategory{byname}{\mkbibbold{#1}}{#1}}

\nocite{*}
\begin{document}
In \parencite{p4, p1, p2, p3}, ``TD75'' and ``Doe85'' should appear in
bold (the semicolon should remain plain).

\section{Co-authored Publications}
\printbibliography[category=byname,heading=none]

\section{Other Publications}
\printbibliography[notcategory=byname,heading=none] 
\end{document}

---

Both MWEs give