Access meeting chat when joining via link

I have a number of meetings which people access only via link (i.e. there's nothing in their calendar). The meeting link is used intermittently throughout the day for actual meetings, but in the downtime we use the chat functionality.

Some people need access to the chat, but won't necessarily be able to join during one of the actual meeting sessions. I can't see any way of making this possible. Does anyone know if there is a way?