Any way to make group chat store history like individual chat?

Currently, when I send a message to someone who is offline, they will get that message next time they log on. However, if I send a message to a chat room, people who join later will not see that message. If I enable history in the chat room they will get it, but they will also get it every time they join. Is there a way to have people only receive MUC messages that were sent since they last joined the group?

thanks,

dave