Asterisk/TrixBox Random Call Blocking

Hi - I have an odd situation and wondering if anyone has any code suggestions.

I have someone that calls me all to frequently - to the point where it is annoying. I know that I can establish code in Trixbox to block the caller entirely but I don’t want to do that.

I’m wondering if there is any way to create code that will “randomly” let the calls from this person through. i.e. every 3rd call will ring through, all others will get a busy signal.

Does anyone have any suggestions or thoughts on this??