Can you attach gameplay effects to the tourism mechanic?

[Mettpawwz]

I'd really like to change the tourism mechanic so that for every 10 tourists you have from a given civilization, you siphon 1 gold from their treasury per turn.

I'm pretty certain there's no way to do this with modifiers but could it be done with Lua? If so could someone give me some pointers? I've only just started to learn Lua.

Thanks in advance.