You have to exit the group and block that person's contact under settings-account-privacy-blocked contacts-add that person number to block...them you can join that group Being in the group you cannot block I think unless you blocked that person explicitly...try and see
I am not in any what’s app group.A good friend tried to make group video calls on what’s app several times without notification.My problem is I don’t want to block her as I value her friendship but want to know if there’s a feature to block her from making video calls just like we can restrict someone from adding us to what’s app groups without our consent.