You can use up to 16 watches, with 1 to 16 robots.
Two possibilities: 1/ The last one to press its watch button is tracked and filmed, or 2/ A smartphone/tablet has the free "PIXIO REMOTE" app. and is connected to the system, it decides who is tracked and filmed, and can also modify many other parameters.
When you receive your extra-watches, proceed to the pairing with your system (see the User Manual), so that each watch has its own radio address. This only needs to be done once, when you receive the watches.