For example: Jess puts in an order for some stuff, totaling $212.17, and enters it into YNAB right after placing the order.
Then the vendor splits up the order into three shipments and charges her in three separate transactions of $17.84, $111.90, and $82.43.
Right now YNAB is going to import those three transactions and treat them as separate from the one that Jess entered for $212.17, which consequently will never clear.
Instead, it would be insanely helpful if YNAB could notice, "hmm, they entered this charge for $212.17 and I don't see it here anywhere, and it's been at least a week since the date it was entered so it should have cleared; but here are three transactions from the same vendor that they didn't enter that total up to exactly the same amount -- let's maybe ask if they're related or something!"