WordPress Ecommerce currently allows you to set the number of tickets available by ticket type/variant type.
In our situation, we need to control the total number of tickets available for an event across all variants. For instance, a particular event allows 20 attendees total. Tickets can be sold as singles at one price, pairs at a lower per-ticket price, and in threes at a still lower per-ticket price. We don't particularly care if we sell 20 singles or 10 doubles, but the total sold needs to be a max of 20. As choices are made, the available number of tickets of the other types should adjust accordingly.
Any pointers on how to get that to happen? Or if it can be added to the features request list?