OCS_GROUP option

[Vic]

Ok, guys, I need some major help in trying to figure out the use of ocs_group.
From what I have read from the manual, if I set ocs_group to yes and login_ignore_queue to false then agent would be added to the campaign based on the queue into which this agent logs into.

What really confuses me is that I am trying to figure out what happens when I have ocs_group = no, login_ignore_queue=false. If I try to log my agent into any queue assigned to the campaign, I get "agent attempted to login into a nonoubound queue"...
So, what is ocs_group? How do we use it?
It looks like I can control which ocs group agent joins, but then, what IS "ocs_group"

Any ideas?
Also, I WANT TO have my agent handle two campaign at the same time!!! I recall reading somewhere that it is not possible. But this does not make sense! Does it?