AI Traffic Variety and the Vehicle Groups Manager

Hello, I have a question regarding the "Vehicle Groups Manager" in the level editor. I understand how to use it, but I was trying to create a high variety of traffic vehicles which the game could pull from rather than spawning the same twelve or so vehicles every couple minutes. So what I did was I added 37 vehicle configs to the VGM window. Obviously, I'm not going to spawn all those vehicles as it would tank my frames. I set the spawn rate to six and checked off "shuffle" (from my observation, all "shuffle" does is pick cars randomly to spawn) I even unchecked "smart vehicle selection" but all that seems to do is only affect AI vehicles created using the radial menu. So, without spawning ALL 37 vehicle configs I have on my list. How would I go about creating an AI traffic pool with a high variety of traffic vehicles so that I won't see the same car every 500 feet? Personally I been beginning to suspect maybe Beam doesn't support this type of configuration due to performance concerns. But I decided I'd post my question here to get in the very least a confirmation of my suspicion.

Thank you in advance!

If you need any screenshots, I'd be happy to provide them.