In accordance with D1.1 (2006, it is the one I have handy)clause 4.1.1.1 requires each manufacturer to qualify their WPS.
"Each manufacturer or contractor shall conduct the tests required by this code to qualify the WPS."
Clause 4.1.1.2 doe allow the Engineer to accept WPSs qualified to different standards, but nowhere in the code are provisions that allow different companies to share the same WPSs qualified by testing.
Best regards - Al