A plugin for the server is only able to act upon clients/players that are connected to the server. It cannot do anything or know anything about players that are not yet in the server.
I think that the best you could do is to kick players when the join the server depending on some sort of criteria.
I don't know anything about Minecraft so I'm not entirely sure how it works but I expect that that feature is built into the the client side of the game already.