The problem with that is that you're expecting them to suddenly realize the problem of what they are doing. I don't know what you call a "long time" but last I checked you're still young >_>, so I don't know if these people really are "long time" friends. I'll leave that up to you, but its best you be frank with them instead of expecting them to figure it out. They may be dumb and wonder why you won't hang out with them.
Well for now I will not be doing anything that has to do with money aroudn them,.