Difficult to work on an urgent problem while having to check multi-chat window constantly to look for any question directed to yourself.
Provide method to direct a comment to a specific person in the chat group. Everybody should see the comment but the targeted person should get a specific alerting signal (sound or color).
Method could be "drag & drop" or autodetect of specific text like "@username:".
You would be able to relax and work on the problem, knowing that you will be alerted with specific signal when somebody needs your attention.