One room rabbit? territorial?

My rabbits are 7 months old. And my slightly bigger rabbit seems to be very territorial in just one room of the house, They were both were in the room at the same time the first. But the bigger rabbit chanced the smaller one, And the smaller one is scared.. Holly (the bigger one) has no problem with the lil one (Gracie) in any other room. Whats wrong with Holly? how do i stop her from chancing Gracie (its not a play run its a mean run)