Sending Multiple Invitations at Once

Our users start mentioning their friends when they open a new topic. We set some restrictions for mentioning, but the first few replays of many of our topics are full of group mentions. In their opinion, it is difficult to want to press the Share button at the bottom of the page and choose to send an invitation. It is also difficult for them to send invitations to only one person at a time.

What solution do you recommend to solve this problem?