Hootz lets you add an unlimited number of contacts that can be assigned to debts. When creating a new debt, simply choose a contact associated with the transaction to always keep track of how much you owe and how much is owed to you.

Additionally, when splitting a transaction, it's quicker and easier to choose an existing contact from the list. Yet, if you haven't added any contacts previously, you can always add a new contact while creating a new debt or splitting the transaction, without having to switch to the 'Settings' tab.