I have 2 main cameras how do i get the Cinemachine brain to only pickup specific virtual cameras?

So i have two main cameras:

Camera Main for the game
A second main camera for my render texture

They both have a cine machine brain, but the second brain defaults to a virtual camera that i don't want to be included in the render texture camera.

Is there a way to setup a tag system, so Cinemachine brain A will only use VCams with tag A and Cinemachine brain B use VCams with tag B?

Or something like that?

I need it for a split screen setup but i don't see any option currently.

Hope you can help.