Hosting multiple dedicated servers 'and' running the game?

[WhompingWalrus]

My PC and my 'net connection are pretty solid, so I'm hosting ~8 dedicated servers at any given time.  All seems to be going well - my CPU never breaches 40% usage, even with pretty heavy traffic on my servers.

My issue is that I can't launch the game to play it myself when I have multiple dedicated server instances running.  One instance is fine - no issue there, I can launch the game afterward using the appropriate params.  If I launch all eight, however, the game either crashes on start or disappears and acts as a background process.  The servers do fine - even if I fire up a ninth instance - so the game, and not the servers which are launched via the same executable, is being pickier about eight dedicated instances than it is about one.  I'm running them at 60 tick, in case it matters.  My RAM, CPU, and GPU are nowhere close to their limits, so it's nothing to do with that, either.

Anyone know of a solution to this?  Also - if I have to close an instance while there are people playing on that server, it migrates host, right?  I haven't tried yet because I'm afraid it'll just sever the connection, which would be a $&*^ move on my part.

Thanks!