I don't think that's possible. Maybe the pool operators could, based on the IP addresses of the workers in their pool, assuming that the miners you're interested in don't change their IP. But chances are they've got other things to do and won't be fighting against their own interests / miners. Hashrate is hashrate for them; and they're right about that.

But what would be the point? Isn't the point that everyone should be able to mine BTC according to their own choices? Is the aim of a free-market and decentralized currency to file users of the currency in question according to their nationality? I don't think so.

I think we're a long way from seeing mass "illegal" coins linked to mining in Russia, I think what the authorities are most interested in are those coming out of certain mixers, for example.