How to share ticket numbers across different ticket types

How to share ticket numbers across different ticket types

I'm running an event and have three different ticket types.
  1. Add on Event + Main Event - Early bird
  2. Main Event only - Early bird
  3. Add on Event only - Early bird
And Standard class - shown but not available until early bird finishes
  1. Add on Event + Main Event - Standard
  2. Main Event only - Standard
  3. Add on Event only - Standard
I only have 40 spaces for the add on event and 150 for the main event.  How do I share the ticket allocation for the add on event between tickets 1 & 2 plus 2 & 3, then rolling them over to the standard version if any are left?

I'm sure this is a common thing that companies do with ticket sales, but I don't see an option to amalgamate the tickets.