SCRIPT for the Console -

const groupID = 'GroupIDGoesHere';
const friends = GetCheckedAccounts('#search_results>.selectable');
InviteUserToGroup(null, groupID, friends);

SCRIPT EXAMPLE for Console - FOR THIS GROUP

const groupID = '103582791470016575';
const friends = GetCheckedAccounts('#search_results>.selectable');
InviteUserToGroup(null, groupID, friends);