I got convinced to use
biblatex and already have the first problem.
I have several
.bib-files and one of them contains only entries which shall be listed in a second bibliography (or even better: a subcategory of the bibliography). It shall look as shown here:
entries from bib-files 1,2,3 alphabetically ordered
entries from bib-file 3
The entries do not have any special
keywords, I don't want to add them manually to categories and I don't want to split the bibliography by chapters/sections/segments/whatever.