We have two health insurance plans, from my wife and myself. Will one offset the other in co-pays?

i have Kaiser, and were about to choose another health plan of choice, either another HMO or PPO from her company, would one or the other offset the other's charges/ co-pay?
--------------------
They don't stack, they coordinate. Your plan is primary for you, your wife's plan is primary for her. Whatever the LOWER copay is, is the one you'll end up paying. When both plans have an 80/20 provision, you don't apply the 80% to the out of pocket amount of the first one - you still apply it to the total bill. So, the first plan pays 80%, the second pays NOTHING, because the total amount payable - 80% - was already paid by the first insurance.
Source