OneWorld Ruby gets you whatever benefits are published for that tier by all member airlines in OneWorld. OW Ruby does not get you all the benefits a member airline offers to its own frequent flyers who hold that tier as in BA allows Executive Club Golds access to their arrivals lounges but this is a benefit BA offers only to its own frequent flyers whose Executive Club status, Gold, make them Emerald within the OneWorld tier system. OW Emeralds from the other airlines' frequent flyer programs are not granted arrivals lounge access because they are the same level as BA's Golds.

The benefit you are requesting is probably one offered to Executive Club Bronze and higher and NOT to all OW Ruby level frequent flyers.