Jeroen 🏳️🌈 Hm, I don't think we're on the same page.
I'm suggesting instead of three transaction (1x A -> 'merchant' or X, 2x B -> A (once on account A as received, once on account B as sent)), in the 'Events' screen (where the three mutations are most visible and cluttering), have these three mutations shown as a one 'Event' that doesn't necessarily have to look like any other transaction, but at least display in a more organised way. It shouldn't just display a mutation from B -> X, but it could show an event stating "Payed from B -> X (relayed from A)" and obviously "Tap for more info", even "Display transactions separately" to ungroup.
There also doesn't necessarily have to be a 'Relay'-button. If you press 'Request' on the original transaction on account A and choose another account from the same user (for example B), bunq could simplify the flow (no 'Accept' in account B) and automatically group the transactions. If mutations 1, 2 and 3 don't happen in tandem, it could at least group 2 and 3 (or any other inter-user-account-mutations for that matter).