>Look for "select_index" in swish.cgi.

thank you very much for your fast reply.  My swishcgi.conf now includes
 
swish_index     => ['Intranet.index', 'Doku.index', 'wwwexamplecom.index''],
select_indexes  => {
                             labels      => [ 'Intranet', 'Doku', ''wwwexamplecom' ],
                            }, 
 
and I'm able to do switch between the indexes via
 
http://127.0.0.1/cgi-bin/swish.cgi?query=test&si=0 <http://127.0.0.1/cgi-bin/swish.cgi?query=test&si=0>  for Intranet.index,
http://127.0.0.1/cgi-bin/swish.cgi?query=test&si=1 <http://127.0.0.1/cgi-bin/swish.cgi?query=test&si=1>  for Doku.index and
http://127.0.0.1/cgi-bin/swish.cgi?query=test&si=2 <http://127.0.0.1/cgi-bin/swish.cgi?query=test&si=2>  for wwwexamplecom.index.
 
However, I can't figure out which URL to use for multiple indexes. &si=0+1 makes most sense to me but returns nothing, &si=0;1 returns only contents of index 0... I'm afraid my understanding of the PERL language is little to none. Would you please give a second hint?
 
Best regards,
Philipp Kappler