Show ticket count for all orders with one particular performance (but not another)

Hi! 

At mona we run a ferry to and from our museum.

I'm trying to get a count of all people who booked one way, but not the other (i.e. one-way riders). Most people book both as its the same price, but we're trying to get an idea of how many fall into this sliver

Both mona-hobart and hobart-mona are grouped into production seasons.

Is there a way to show everyone that went mona-hobart without a hobart to mona in their order?

Thanks for any help! Not sure if I need to resort to SQL for this one (feel free to show me how how you'd do it in there if thats easier). I can do in list manager, but it doesn't include the 0 GP constituent, which is the bulk of our orders.