Thanks for the suggestion! I know Splitwise isn’t perfect for people using large numbers of currencies all at once, and that’s something we want to keep improving over time. I’ll add this to our list of possible improvements for the future :)
Thanks for the suggestion! There is a very basic version of this feature on our website – click on a specific person in the left sidebar, then click the settings icon at the top of the right sidebar and choose “Consolidate debts with this person”. All your groups will be settled up, and the remaining balance will be transferred to a single non-group bill.
We’ve also thought about a few other versions of this feature, but unfortunately it’s been really difficult to find a design that doesn’t confuse people. (Even the single-group “simplify debts” feature confuses a large percentage of people.) For now, we’ve decided to leave out any more complicated debt shuffling features, as the increase in confused/frustrated users seems to outweigh the benefits. Apologies for the trouble!