Reviving an old thread because I found a really simple solution. Hopefully 
this will also be useful to someone else.

On Mon, 18 Oct 2010, Wolfgang Schuster wrote:

>
> Am 18.10.2010 um 14:18 schrieb Otared Kavian:
>
>> Your solution works as intended when the framed, highlighted text with background spans over two pages (though it doesn't when it spans over three pages or more, but this is not a real issue, since it is a bad idea to have such long highlighted texts…).
>
>
> I guess this is also possible with textbackground:
>
> \newcounter\CurrentBackground
>
> \def\StartBackground
>  {\doglobal\increment\CurrentBackground
>   \setposition{Background:b:\CurrentBackground}%
>   \startbackground}
>
> \def\StopBackground
>  {\stopbackground
>   \setposition{Background:e:\CurrentBackground}}
>
> \def\DrawBackground
>  {\ifnum\MPp{Background:b:\CurrentBackground}=\MPp{Background:e:\CurrentBackground}
>     \startMPcode
>     draw topboundary    OverlayBox withcolor red ;
>     draw bottomboundary OverlayBox withcolor red ;
>     draw leftboundary   OverlayBox withcolor red ;
>     draw rightboundary  OverlayBox withcolor red ;
>     \stopMPcode
>   \else\ifnum\realpageno=\MPp{Background:b:\CurrentBackground}
>     \startMPcode
>     draw topboundary    OverlayBox withcolor red ;
>     draw leftboundary   OverlayBox withcolor red ;
>     draw rightboundary  OverlayBox withcolor red ;
>     \stopMPcode
>   \else\ifnum\realpageno=\MPp{Background:e:\CurrentBackground}
>     \startMPcode
>     draw bottomboundary OverlayBox withcolor red ;
>     draw leftboundary   OverlayBox withcolor red ;
>     draw rightboundary  OverlayBox withcolor red ;
>     \stopMPcode
>   \else
>     \startMPcode
>     draw leftboundary   OverlayBox withcolor red ;
>     draw rightboundary  OverlayBox withcolor red ;
>     \stopMPcode
>   \fi\fi\fi}
>
> \defineoverlay[DrawBackground][\DrawBackground]
>
> \setupbackground[background=DrawBackground]

A much simpler solution using textbackgrounds:

\startuseMPgraphic{splitframe}
   for i=1 upto nofmultipars :
     if one_piece_multi_par :
         draw multipars[i] ;
     elseif multilocs[i]=1 :
         draw topboundary   multipars[i] ;
         draw leftboundary  multipars[i] ;
         draw rightboundary multipars[i] ;
     elseif multilocs[i]=2 :
         draw leftboundary  multipars[i] ;
         draw rightboundary multipars[i] ;
     elseif multilocs[i]=3 :
         draw leftboundary   multipars[i] ;
         draw rightboundary  multipars[i] ;
         draw bottomboundary multipars[i];
     fi ;
   endfor ;
\stopuseMPgraphic

   \definetextbackground
     [splitframe]
     [state=start,
      mp=splitframe,
      location=paragraph]

\starttext

\startsplitframe
   \input knuth \endgraf
\stopsplitframe

\blank[big]

\startsplitframe
   \dorecurse{4}{\input knuth \endgraf}
\stopsplitframe

\blank[big]

\startsplitframe
   \dorecurse{10}{\input knuth \endgraf}
\stopsplitframe
\stoptext

Aditya