Is there anyway to add subscribers to a message when someone makes a comment ?

The scenario is the a message exchange may begin between a select group, as the thread develops, we want to get more people involved in the discussion as it evolves. There only way I can see is for the original message creator to edit the message and add people. I couldn’t do it at a comment level.

It can be annoying because clients which are only part of a project may not know who needs to be on a thread from the word go and to have to ask them to continually add people is annoying.

Is there a feature to add subscribers at a comment level that I can’t find, or is it not a feature of the system ? The other alternative is that someone with access to a project can go and add themselves into the subscription list.

The person who originally posted the message, or any admin, can edit the message and check off additional names to be notified via email when there are new comments.

This has always been the case in Messages, but what about To-Do comments?
Oh my bad…just saw this: when I edit the original comment it says “add files…or edit notification options.”

What I have found though is that the original author can’t edit the message and tie it to a milestone. The option is only there for the site admin.