Any way for Gaia units not to get converted?

I'll try to keep this quick & simple.

Basically when you create something in the Scenario Editor, there's a "player" called Gaia which can get a lot of other units like animals and such, and they have both unupgraded units (like Spearman) and the later versions (like Halberdier), so it can be really useful, and is one of the reasons I want to use it.

HOWEVER, all Gaia units except most animals and the Bandit AFAIK get converted to Player 1's control once they enter one of Player 1's line of sight. I have an RPG map that has Gaia units that don't get converted though, and one of the human players is Player 1, so I assume there is a way to make Gaia units not get converted. Is there a way that I can do it myself?