No problem. DME can be used roundtrip, one-way inbound, or one-way outbound, regardless of airline.
So just make a one-way inbound reservation for your first Disney resort. And make a one-way outbound reservation for your second Disney resort. Each DME reservation should reference the corresponding resort reservation number.
Because you are flying on an airline that participates in Resort Airline Check-in, you have that option available to you when it's time to fly home (unless your flight is too early in the morning).