Custom Privacy/Screening Menu

Hi all,
I’m aware that you can use the ‘p’ flag to do a call screen when you call. I’m looking for something a bit more custom. First I’ll explain why:

I allow callers to contact my cellphone. When they try to call me, I change the callerID string to match my actual outgoing number. This lets me unlimited airtime to/from my PBX. When I do this, I lose the callerID information of who’s actually calling me. What I’d like to do is place the calling party on hold, dial my number, play a text-to-speech of the calling party and prompt, asking to either connect or reject the call. I’m not quite sure how to do this. Any help?

Thanks!

This is what the M (deprecated) and U Dial options are for. I think you could also achieve it with G.