Here's the logic for the PLR/ToW hybrid mode used in stage 3 of Guava Gulf. Carts begin as in a standard PLR mode, but can merge onto the same track to become ToW. Once a team makes it to the other end of the zone, the carts separate again.
This version of the logic is designed for Single Stage PLR. It can be modified for use in a multistage setup (which is what I did for Guava Gulf), but keep in mind it is very complicated to do so and you'll need to fight a few engine bugs to get it to work right. I don't recommend doing this unless you already know your way around the payload entities well.
The carts themselves are heavily modified as well, so using just the tracks in your map will do nothing. The carts have different collisions, speeds, and I/O than the default payload cart setup found in most other maps in order to allow for the ToW section to work properly, so please use the ones included.
Single Stage PLR logic originally from @A Boojum Snark's Ultimate Mapping Resource Pack, heavily modified using @Ynders' Tug of War Payload Prefab as a reference.
If you're curious as to how it works, I recommend opening it up and takings a look for yourself before asking questions. It's a complicated system with many moving parts that are hard to describe in text!