I'd like to make the AI in a map hold a line and fire at the other team, rather than the typical running into a disorganized mass of units from both sides. I placed hint nodes and tried several different types, but the AI simply ran past them. Is what I'm trying to do within the limitations of the game's planning system?

I dsont know if this is possible, but you could create a temporary barrier, or just make planning that goes in a line, so when they reach it, they run down the line, shooting.