Just tell them "We gotta talk" and explain the situation. Make sure you have it down on all the points you want to address. Keep it good natured and ask them what they think as you explain and see the reaction, this will tell you what you have to do. If they balk, which they shouldn't if you're being fair, then you might have to take the action you're thinking about, but it might create bad vibes. If this is bothering you this much, you probably have to clear the air and don't get the idea that they all know what you are feeling, they probably don't have a clue. Good luck.