Herd bound pony...help!?

I have a 14hh Fell x Thoroughbred who is perfect in every way, except that she doesn't like to be separated from her field buddies, esp. the gelding. It's not a huge problem, she'll still hack out alone, load, etc., but at our yard there is no restricted grazing, so I need to keep her off the gr for part of the day. At the moment she's coming into her stable, but she hates it - keeps calling for her friends, pacing, and kicks the door if I don't put up the grille. I put up a mirror about 1 meter square - this worked wonders on my last horse - but she ignores it. I do have a gr muzzle but that sent my last horse into a horrible depression - she refused to eat or drink through it, stood in a corner looking pathetic, etc. Would like to avoid it. Any ideas for getting her to settle in the stall for a few hours a day?