My friend makes me mad

Everytime we play together on minecraft or something like that i always say I WANT ONLY US TOO PLAY AND HE GOES ON DISCORD AND GETS OTHER PEOPLE TELLING THEM TO PLAY WITH US i hate being in groups i only like to play with ONE person at a time and he invites f***ing 50 other people! It's driving me nuts! How can i tell him to ******* stop