Yes i'm thinking about some rules for the communities I run.
I think they have to have posted it to another community first if they want to post to our community. Or burn reward (upcoming button feature)

If they post to a home page then our community it seems greedy because they could have easily posted to the community and then did a resteem.

Not saying those posted to a home page first can't be reshared but maybe that's at a moderator's discretion.