If I understand Will's response correctly (under "Earmarking"), it's best to think of GWWC, 80K, EAA and LYCS as separate organizations (at least in terms of whose money will be used for what, which is what really matters). I don't know if this addresses your concern though.

I admit it makes the actual physical donation process look slightly clunky (no big shiny donate button), but my impression is they're not targeting casual donors so much so this may not be such a problem.