ConTeXt: Four-column footnotes within two-column page layout

Question

I have made a document test in ConTeXt. A two-column layout with four-column footnotes. I need to place the footnotes of each page at the bottom of text area, within a frame.

My ConTeXt script places all footnotes on the last page.

Output

First page:

Second page:

Code

\startenvironment enviro-mmi
    \definepapersize[mmi][width=6.5in,height=9in]
    \setuppapersize[mmi][letter]
    \setuplayout
    [
        backspace=0.875in,
        topspace=0.5in,
        header=0.5in,
        footer=0in,
        width=5.125in,
        height=7.5in,
        margin=0in,
        marking=on,
        location=middle,
    ]
    \dontcomplain
    %~ \showgrid
    \showframe

    \setupbodyfontenvironment[default][em=italic]
    \usemodule[simplefonts][size=9.5pt]
    \setmainfont[utopia]
    \setsansfont[Roboto Condensed]
    \setupindenting[yes,next,0.1875in]

    \definemixedcolumns[col2]
    [
        n=2,
        grid=yes,
        align={width,verytolerant},
        separator=rule,
        rulecolor=middlegray,
        rulethickness=1pt,
        balance=yes,
    ]

    \definemixedcolumns[col_notes]
    [
        n=4,
        align={flushleft},
        %~ separator=rule,
        %~ rulecolor=middlegray,
        %~ rulethickness=0.5pt,
        balance=yes,
        grid=no,
        distance=0pt,
    ]

    \setupnotation[footnote]
    [
        style=\ss,
        align={flushleft},
        width=fit,
        numbercommand=\ss\bf,
        margin=13pt,
    ]
    \setupnote[footnote][location=text]
    \startsetups flushnotes
        \framed
        [
            frame=on,
            offset=6pt,
            rulethickness=1pt,
            framecolor=middlegray,
            width=max,
        ]
        {\startmixedcolumns[col_notes] \placenotes[footnote] \stopmixedcolumns}
    \stopsetups

    \starttext{}
        \widowpenalty=10000
        \clubpenalty=10000
        \startmixedcolumns[col2]
            \input Knuth\footnote{FreeBSD tire ses origines de l'UNIX de Berkeley.}
            \input ward\footnote{This does not seem to be implemented yet.}
            \input hawking\footnote{Left, right (raggedleft, raggedright).}
            \input Knuth\footnote{Distance between columns.}
            \input ward\footnote{Draw a line between the columns. Default is off.}
            \input Knuth\footnote{FreeBSD tire ses origines de l'UNIX de Berkeley.}
            \input ward\footnote{Draw a line between the columns. Default is off.}
            \input hawking\footnote{Left, right (raggedleft, raggedright).}
            \input Knuth\footnote{Distance between columns.}
            \input ward\footnote{Draw a line between the columns. Default is off.}
            \input ward\footnote{Draw a line between the columns. Default is off.}
        \stopmixedcolumns

        \setups{flushnotes}
    \stoptext
\stopenvironment

Answer 1

What I get here is this:

\setupfootnotedefinition[alternative=left]
\setupfootnotes[n=4,columndistance=2em]



\starttext

\input ward\footnote{This does not seem to be implemented yet.}
            \input hawking\footnote{Left, right (raggedleft, raggedright).}
            \input Knuth\footnote{Distance between columns.}
            \input ward\footnote{Draw a line between the columns. Default is off.}

\stoptext