Another #CrossBorderRail ticketing annoyance: while the Nightjet website allows booking tickets for several people at once, and allows booking Interrail reservations, it doesn't allow booking a regular ticket + an Interrail reservation on the same train in one transaction. You can configure 1 regular adult + 1 Interrail holder in the search bar but get blank results.
And if you make 2 separate transactions, there's no guarantee to end up in the same compartment...

