Specifically what I’m looking for is a type of AI that is used commonly in Shadow Dragon and Three Houses.
It is basically fe12 linked AI flipped on its head. Basically certain enemies are grouped together and if the player enters the range of ANY enemy within the group, every unit in the group begins moving regardless of whether or not they are able to attack on the same turn. This prevents the bait and switch strategy that dominates a lot of vanilla fe8, but in a way that is much more fair and fast paced than fe12’s linked AI.
Is it possible to recreate this in gba fire emblem using the FeBuilderGBA tool by means of a technique or a patch? I know I can probably do it through eventing, but I’m still learning how events work and it sounds incredibly tedious to make an event for every enemy group. If it isn’t possible, I can just use 2-3 tile wide wall cracks and drawbridges/snags to recreate the effect, or very meticulously placed (move if can attack within 2 turns) enemies, but simply having an AI option will give me much more freedom in map design.