I want to book IAD-LAX-MEL roundtrip and use a GPU to upgrade each way.
Availability shows 0 R class available when I check IAD-MEL each way. But when I check just LAX-MEL roundtrip there are 9 R seats available each way.

My question here is if I purchase IAD-LAX-MEL-LAX-IAD, when trying to upgrade, do you think I will be able to get the upgrades on the LAX-MEL-LAX and waitlist for the domestic legs?

I'm just not sure how this works. I know I could purchase two separate tickets but want to avoid this as I would like to get the advantage of using a single GPU each way even if it means being on a waitlist for the domestic portion.

Thanks