in that case, every time you enable 1 camera, disable the other.
or maybe this is just a hacky solution, and you should really just use 1 camera teleporting around, and maybe separate the camera from the character.
you could put all the effects in your camera actor, with functions for setting the distance, offsets, FOV, Letterbox, post process modes, etc… and make it detect custom physics volumes that can override effects. you should probably always use 1 camera, just teleporting it around or interpolating it along splines or attaching it to bones or whatever you need, and set your view target to this camera actor, instead of your character.