Call service with blacklist

I am writing a small call back application that shall offer the possibility for the called party to abuse the caller.

This is the scenario:
I use a dial file for callback to the caller.
The caller is then asked to wait wile I connect the destination
I Use Dial command with h option and a Macro to offer the destination an IVR to accept or decline the call.
If accept teh call is connected.
Simple and strate forward.

What I was hoping was to use h option to allow the called party the possibility to hang up the call if the caller is noghty or so by pressing ** or watever is defined in feature.conf file.

But I can not find a way to determin if the called party pressed ** or just hangup, no I do not know if the called party likes to abuse/blacklist the caller.

Any hint on writing my dialplan?