Grabbing Jerseys

[tarheelcoach]

We have a couple of coaches that teach their players to grab the offensive player's jersey to prevent them from getting open.
Last year, one team was doing it all game. I talked to the refs about it, but they couldn't catch them doing it (I know it can be hard to see - especially in the post where the players are so close together.)
I told my players to knock their defender's hands off, and my center got nailed with two flagrants for it.

What would be a legal way to get a defender who is grabbing the jersey off?