In some cases, it's convenient to break a loop into two loops where you have one loop iterating according to one input element, and the second iterating according to a different input element. To do this, split the loop by right-clicking on the element and selecting Split Loop.
For example suppose your output has a loop for street addresses (of any type), where many different addresses are supported. And the input has a loop for business addresses and a different loop for personal addresses. To easily map this, you could split the output loop into two loops and map the first to the business addresses and the second to personal addresses. You can split a loop into as many loops as you like, and if you no longer need a split loop you can delete it.