| From what I could work out, xfire will tell you which server someone is playing on if you click the "extended info" button which is the arrow on the right-hand side of xfire.
You should then be able to click the Joypad icon to jump into the same server and join them.
However.... we couldn't get this to work last night, but chances are we were doing it wrong anyway, so we simply used xfire as a messaging tool to let each other know where we were.
It may be that xfire doesn't fully support HL2DM as it's so new, and it also seemed that the Steam server auth was knocked out (or dodgy at best) last night too, so that may also have caused problems. | 
antonye
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