It's a well known 'secret' that Bluetooth should be coming to PAW very soon. If you have a Bluetooth headset then that would be a very easy fix to the problem.
If you wanted to plug your PAW into the radio and have SD over Bluetooth then you could always stick a 3.5mm BT transmitter into the jack of your iPad (or similar) and get SD audio that way.
If you don't have a BT headset then a suggestion on another site is to have some in-ear BT 'buds' which would be able to receive the BT outputs from either of the above.
If you do want to combine both inputs into the radio/intercom then you'll need to have some sort of mixer. If you search the Forum for this you'll find I've already made a nuisance of myself and asked quite a few questions about it
Finally, if you search for Bluetooth on this Forum you'll find a suggestion for a cheap way of 'mixing' audio inputs and a BT receiver into a little 'star' sharing device for several sets of headsets to plug into.
Wiring up the TT21/22 has also been explained in some depth recently and sounds really quite simple, even to me
Seriously, the search function will reveal all you seek.