Has anyone come across a solution for marking off attendance of registrations for a group booking in Zoho BOOKINGS?

My client needs to be able to set up a group meeting at a defined location and time and invite people to register their interest in attending. 

Further to that however, we want the ability to capture the fact that they indeed attended. 

The catch is, these meetings are conducted around the world by 100's of different people but all convened by the company (my client). The person conducting the actual meeting is not a Zoho users (this si simply cost prohibitive) as they are in fact an external party to the business.

Anyone got any brilliant suggestions on whether this is possible and how we should approach the problem.

They currently manage this through Zoom but we want to capture the registrations into the CRM to be fed into the sales funnel.

TIA