MTG Returning lands at upkeep
At the beginning of your upkeep:

Both instances of the card will put their own triggers onto the stack.
You can choose which order the triggers go onto the stack, not that it matters very much.
The stack resolves in LIFO order as always.
The first trigger resolves. You can choose whether to return a land to your hand or sacrifice the specific instance of the card that created that trigger.
The second trigger resolves. You can choose whether to return a land to your hand or sacrifice the specific instance of the card that created that trigger. This is a separate event from the first trigger resolving, so you cannot return the same land or otherwise count that because that land is already back in your hand.

tl;dr: you need to return one for each.