Flying AA to DFW, in first class, to connect to AA flight to GRU, in biz class. Normally we could use an Admirals Club, but at SEA there is no club. To use Alaska Airlines' Board Room, we'd have to have both the usual boarding passes and Admirals Club membership (once we get to DFW, no problem using the Admirals Club). We have an Am Ex Platinum Card, but it appears that would just get us into the Delta Club by the "S" gates (which I assume is the South Satellite terminal, far from the D Terminal, from which we'll leave). Is there in fact no club we could use without buying a one-day membership?