Modding

Good day. How can I make the gates of a siege arena in any castle open by default, as they usually have open gates: animation "open", ONESHOT_STILL, or is there another way to achieve this? I need open gates for decorating the battle arena; animations cannot be played there because playAnimation() only works on units/heroes. Do you have any ideas besides the tedious process of using ArchanGel, 3ds Max, and reverse importing?