Hello

Please consider allowing for an option to set the number of transactions/purchases on a project.  

There are instances when there is an event and only a certain number of tickets are available for sale.  It would be great if the system, could:

1. Send out a notification to the administrators when 80%/90% of the tickets/event bookings has been sold/paid.

2.  Not accept any more payments for an event/ticket when the set number has been reached.

Thank you.