You could setup skills with the same name as your CSQ and configure the CSQ for skill routing, like this:
CSQ1, skill CSQ1, min. level 5
CSQ2, skill CSQ2, min. level 5
CSQ3, skill CSQ3, min. level 5
Then assign the needed skill to the agents that you want to be part of more queues.
Agent 1, skills: CSQ1(8)
Agent 2, skills: CSQ1(8), CSQ2(8), CSQ3(8)
But I am not sure if this is what you want, as you are not providing to many detailed info.... ;-)
Hope it helps,
Leo