Events module - linking nominated 'number of attending' event to 'Maximum number of Participants per

Hello topliners,

I'm hoping someone can help me with the events module.

I have created an event booking form for a campus tour. In the form, registrants are asked to nominate the number of people attending from a picklist (options 1 - 7).

In the events module - event actions, I have set the 'maximum number of participants' to 7.

I would like to link the field value for 'number of attending' to update the event actions above. So if an attendee completes the booking form and nominates 7 attending, all new registrants will either go to a wait list or be unable to register for that particular session.