The behaviour is around any mare, not just one or two in particular; even if they are not at all interested in her.
Also the behaviour doesn't calm down. I tried her next to other mares for 5 months and she was practically unhandleable for the whole time :/
Your advice/experiences please!!
My mare comes in to heat when stabled or turned out with/near to other mares.
At the same time she becomes absolutely obsessed with the other mare; becoming aggressive if you try to take her away from the other mare, and extremely anxious if the other mare...