Apologies if I’m reading your question wrong, but if you go to the Options tab and then expand Targeting Options, uncheck everything there and it will turn off all automatic loading of teams and stuff.
If you mean how to disable summoning a pet to your side when you load a team, generally that’s hard-coded into the game; but under Miscellaneous Options is Keep Companion to summon the pet you had out before the load, or dismiss the pet if you had none out before the load.