Yes and it is pretty simple.
Figure out the Mic wiring
Get a STDP (ON-ON).
Wire the ground to the center pin of the switch
Transmit Wire to one of the outside pins
Recieve to the last pin
Switch in one Position will be RX, flip the switch for TX
If you want to be real cool use a DPDT switch.
Wire the audio line to the same side as the TX Line
Feed the Positive side of Signal Generator audio to the center pin on the Audio side of the switch.
You can set the radio In TX mode and inject a 1kHz tone to the Mic audio to set modulation levels with an O'Scope...
Make it look like this:
Just a thought