Title says it all. I have a fortress-like arena, and I have the mobs spawning outside of the walls. However, the mobs simply stand there and don't attack because they are too far away, making them easy pickings for archers. Is there a workaround for this, or do I need to rethink my design?
EDIT: I forgot to add that I'm using the plugin MobArena to control my arena, thus probably limiting the customisation with the mobs.