Extract similar dates from multiple date lists

[nouslouons.france]

Hello everyone, here is a problem that I have not been able to resolve for a long time, although it is not for lack of trying.

Simplified explanation: I have several lists of dates in the database, and I need to highlight the dates that appear in common in all the lists. These dates common to all lists will be placed in another list. How to do ?

Detailed explanation: my users can create product listings for rent, and then also create product inventory for each listing. Example: an advertisement for a bike to rent may have 4 product stocks (4 references) for the same product.
When a user rents a bike, the owner chooses in his management space the reference that is rented, which will therefore no longer be available on the reserved dates. When all references are rented on the same date, this date must no longer be reservable. Any idea how to do it?

Below is an image of the product stock database (references), we can see on the far left that it is associated with a specific ad. The dates circled in red are reservation dates.

Below is an image of the announcement database, we can see in red the “unavailable” dates which are supposed to be those which are reserved in all references.

I imagine there are several ways, perhaps by comparing lists, or extracting data, or with backend workflows… I’m open to anything!

Thank you in advance for your creativity and help

[GaryIreland]

its going to come down to a condition on the workflow that does bookings. When someone tries to take a slot you need a do a search for action that stops the workflow when none are available. I’ve always struggled with manipulating dates in bubble so can’t specify the exact expression you’d need.