Hello,
Use Rankings. Only the constituents with that ranking (or higher) can get tickets. They would have to login first. Can combine rankings and MOS.
We do this with our Gift Shop (a separate company). We added a ranking to their constituent record, as well as a new attribute. When they login on our TNEW site and click Admissions, instead of seeing our admission performance, they see our ZooBuck performance (MOS shift) which they exchange our gift certificates for ZooBucks. The ZooBuck performance can only be accessed online by our gift shop vendor because their record is the only record with that ranking. TNEW shifts the MOS to a MOS only accessible to those with the attribute. The performance only has the one online MOS available to it that the rankings allow. The gift shop uses the guest’s Tessitura gift certificate to pay for ZooBucks and pretend they physically have them for payment of items from their store. We both get nightly scheduled reports and settle up monthly.
Long story short, look into rankings.