I am flying EUG - SFO - EWR - LHR. I bought two separate tickets to make up the route one (in J) from EUG - SFO - EWR and one (in Polaris, as an award ticket) EWR - LHR. My flight to EWR arrives in the afternoon and my flight to LHR leaves the same evening, with plenty of time between. I have a couple of hour layover in SFO as well. The PNRs are cross-referenced, but separate.

I can clearly access the Polaris lounge in EWR, but my question is whether I can use the SFO Polaris lounge on my layover at SFO. I believe the rules are bit unclear, and I am wondering if anyone has had any experience in this situation and what the result was.