Correction, I'll happily look into a solution that satisfies BOTH parties, but I won't favor your side or their's.
I would much rather come to a conclusion that benefits both parties, but I won't make it blatantly easy to secure kills by removing agro entirely, hence the re-location idea.
How about an accessible area around 30-40 wilderness with nearby escape potential a few levels up or down, which offers them a chance to escape and y'all have it your way to an extent as well.
I offered a solution that benefits both sides rather than entirely playing into the hands of a specific group of Players (PKers), I won't side with anyone or meet your every demand, I'll do what I can within reason.
PS: that wasn't intended as flamebait but a genuine comment, should Gorilla's be re-located (will make a thread later) and they still manage to escape that's entirely on your team.
Sincerely, Shirou.