Hello,
I can help you out with this. I took at a look at the site and thought it related more to membership then event tickets. Our Add Ons do not really do anything for membership.
We do have our Ticket Add Ons for different e-Commerce Plugins and for example with the WooCommerce Tickets you can create 2 or more tickets of different prices for an Event.
That might get your close to what you are asking.
Let me know if you need anymore help.
If I got it wrong on what you are looking for could use please outline the steps you are looking for users to take and I can help get you in the right direction then.
Thanks