Limiting a field choice on two different forms based on a common field

Hi,

I'm somewhat of a FF newbie and can't wrap my head around how to solve this issue, sorry for the incoming wall of text.

I've got two forms that manage booth signups for a festival, each form handles a different type of booth holder, sponsors and artists. They've got very different field sets so they were set up as different forms. But now several years into the festival we've realized that one of the headaches is managing the booth placement from the different forms and we want to allow the applicants to pick a preferred area for their booth. Each area has a variable number of booths it can hold. My vision is that the forms would have a dropdown allowing them to pick from the areas that aren't full yet.  So Alice fills out the Artists form, picks the Northwest area (which holds ten booths) and is the tenth person to pick that area. Then Sam fills out the Sponsor form but he can't pick the Northwest area since it is now full.

Is this doable with two forms (artists vs sponsors)? Do I need to combine them? I was looking at the nested view page in documentation but couldn't follow how this would fit the issue.

Many thanks in advance for any shoves in the right direction!