The AI can't use the radio. You have to do it for them.
Say for example you want an infantry squad to have air support. If its player led it's easy, you just give him a radio trigger. If it's AI led you still have a switch trigger to make the CAP come in, but instead of being activated by the radio it has to be activated by something else.
That something else might be the tanks arriving in certain place, or it might be the AI squad taking casualties, or pretty much whatever you like.
As far as the tanks are concerned, they can't tell the difference. ... they meet some infantry, and after a bit the infantry get air support. Whether its a radio trigger or another kind of trigger makes no difference to them.
Does that make sense?