You can log on to the MERGE site from different "skins" Reefer, Walker, Nordica,PDC,Carbon, Wass but not all games appear on all sites, at which time you'd have to download the skin hoisting the game.
Each site also requires a different screen name - so if you tried to play at Reefer for an OFC game hosted on Carbon, you would have to be on the site your ticket actually is - EG you couldn't play that way.
The software does not allow you to log on from the same ISP with different names to multiple sites either.