I know I can block calls from unknown but it would be nice to ba able to allow unknown in my home country ( 39). Is there an easy way to do it?

I know I can block each single caller and I know I can block anybody not in my list of contacts. I feel these 2 options are a kind of 2 extreme solutions. I'm looking for something like either blocking unknown callers from a specific country (e.g. +1) or blocking all unknown caller outside my home country (+39). Any idea? Any chance for a development on a future iOS?