[Xymon] how create a multi-http graph?

Hi all, i need to create a http response time graph for multiple hosts. I have added in graphs.cfg this section:

[http-multi] TITLE Multi-host HTTP Response Times FNPATTERN tcp.http.(.+).rrd YAXIS Seconds DEF:p at RRDIDX@=@RRDFN@:sec:AVERAGE LINE2:p at RRDIDX@#@COLOR@:@RRDPARAM@ GPRINT:p at RRDIDX@:LAST: \: %5.1lf%s (cur) GPRINT:p at RRDIDX@:MAX: \: %5.1lf%s (max) GPRINT:p at RRDIDX@:MIN: \: %5.1lf%s (min) GPRINT:p at RRDIDX@:AVERAGE: \: %5.1lf%s (avg)\n

and i have used this url (work for multi-la):

https://xymon.server/xymon-cgi/showgraph.sh?host=server1,server2&color=green...

but don't work.

Any suggestions?

thanks Marco