Annie would do this when we took her off to our trainer's barn. Especially
around feeding time. How we got her to stop:
I would take th elunge whip with me and every time she tried to ram through me, I would crack the whip (Not hitting her, God forbid, just making sure I got my point across) and drive her backwards. She responds well to a whip so it worked out well. I would go in, crack the whip, and make her stand in the back of her stall until she relaxed. Once she was relaxed, I would try and walk her out again. If she repeated, I would proceed to drive her backwards. She soon learned that every time she tried to run out and over me, she would be delayed that much longer. When she walked out pleasantly, I would scratch her under the neck where she likes it.
I had someone at the barn mention a differant technique too. (Just some random stranger walking by....didn't know him.) Every time she charged out, use the rope to drive her in a mini-lunge circle around you. Basically its "You wanna move? Okay, let's move!" trick. So the idea behind that is that she learns that every time she charges off she has to do more work than she really wanted to, and starts thinking maybe it would be easier just to stick with her mom and be good. I generally use that technique for the horses that like to run ahead of you on the lead rope.
Hope this helps, they've worked pretty well for me in the past.