Currently, biter nests can appear close to demolishers. Both are on the same faction with no "friendly damage" which just looks wrong.

What would happen if demolishers were placed in their own faction? Would biters war with them? Probably biters would get squished from time to time but without any major outcomes (besides demolishers keeping biters out of their territory). Maybe with late-game evolution biters could sometimes kill small demolishers. Seems interesting to try, if this isn't too hard to implement (since demolishers can't spawn maybe it's sufficient to set the faction on map load).

I don't suggest changing the Nauvis (Biter) / Gleba (Wriggler) factions.

Thank you very much for the suggestion!
I did some testing, and it was fun setting the demolishers to fight with the biters, but probably a step a too far.
With the uploaded version 0.15.0, demolishers will now destroy biter/worms/nests on the demolisher's path.
While not fun, it does at least address the "looks wrong".

Demolishers are assigned a new force eon-demolishers, then friends and ceasefire are set true between the forces. No fights, but destruction.

Sounds like a good compromise.