I will be travelling on a SouthAfricanAirways ticket (SA) the following route:

Johannesburg(JNB) - Perth(PER) flying SA, and ***on the same day *** Perth(PER)-> Melbourne(MEL), but using QANTAS(QF) on this leg . Can I use the *A lounge in Perth(PER) ?

And return

MEL->PER (with QANTAS) and ***on the same day*** PER->JNB with SA. Can I use the *A lounge in MEL ?

Obs: I am United *A - GOLD and also TAM *A - GOLD.

Thanks much