Any way to avoid randoms joining you?

[Johambubger]

Trying to grind out the weapon kills as quickly and painlessly as possible. I know you can't get trophies in a private game, and putting a password on a public(?) game gives me a warning about how trophies won't be unlockable then either. Am I missing something? Randoms keep joining my game and messing up my flow.

[LOG-FX]

Changing the server region and turning off the cross platform can be useful. I hardly got randoms joining in my game.
Moreover,  as long as you do not use private matches, you can use Genetically Modified Options. Big Head, Random Weapon and Big Heads are useful for grinding kills.