I have found a way to use unique GoToMeeting links, not the personal meeting room that is “always open”. It’s a bit of a hack job, but I think it will work.
We’re using Office365 and I have the GoToMeeting add-in installed. I can click on Scheudle Meeting which creates an Outlook calendar event with a unique meeting url that I send to myself with the correct date and time. I’m guessing you could probably do this from within the GoToMeeting dashboard itself too, but I’m already in Outlook. I can then copy and paste that meeting link info into the HubSpot meeting description, so the contat will receive it inside of their HubSpot meeting confirmation email.