Hello.
Unfortunately, if you are need to make the several reservations per the same timeslot at same date, so its not possible in any versions of Booking Calendar. Please check my suggestion bellow about that.
At the Booking Calendar Business Small and Business Medium versions are possible to make the bookings for the specific time slot.
Please note, if some visitor will reserve the specific time slot at selected date at specific booking resource (calendar), this timeslot become unavailable for the other visitors at this selected date in this booking resource.
At the Booking Calendar Business Large version is possible to set the capacity of the booking resource, it’s mean that your visitors can make the several reservations per the same date, in other words, the date(s) in calendar will be available until lumber of reservations per these full dates is less than capacity of the booking resource. Please note, if you will use the timeslot selection for the booking resource with capacity higher than one, so then this timeslot will be simply record as a data into DB according this booking, but will not impact to the time availability.
Please read more info about the booking resources and how to configure them here https://wpbookingcalendar.com/help/booking-resource/
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Suggestion! I can suggest that you can create the booking resource with specific capacity for the each of your times and then have the independent own calendar for the each of your time slot for the reservation. Its mean that your visitors firstly, need to select the times in the selectbox, and only after that select the date and fill the booking form. Its can be look like this: https://bm.wpbookingcalendar.com/select-resource-2/
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You can define the specific dates as season filters and then set them as unavailable at the Business Medium and higher versions.
