Team antagonists are required to work with members of their team, but not any other antagonists. No other antagonists are required to work with any other antagonists.
As long as it does not conflict with their specific rules, team antagonists are free to choose to cooperate with antagonists not in their team, and other antagonists are free to choose to cooperate with other antagonists. The requirement that this cooperation not violate the antagonist’s specific rules means that, for example, team antagonists cannot cooperate with an antagonist to the detriment of their team.