@Robert , approach 1 works like this:
Events 1 mio per hour Distinct Object: 100000 Order is needed Topic hierarchy is salesOrder/{salesOrderID}
Exclusive queues, with subscriptions:
Queue0 → salesOrder/0*
Queue1 → salesOrder/1*
…
Queue9 → salesOrder/9*
That gives you your 10 parrallel consumers with ordering strictly maintained.