What PMS module?
You need to elaborate.
Separate why? If you make a new entity type for rooms they can be in there own entity screens and have their own states.
On my NewBook PMS setup we use at the 3 hotels here I have it that way and scripts to link to our separate PMS.
They are not in a ‘module’ which I don’t really understand what you mean by. This means you can have room and table on a ticket, table while eating but room selected ready to charge to at the end.
Maybe you should look at that setup as you plan to use Google calenders you might set some ideas.
It’s a bit topic but lots of info in there;