Special users / users with different classes

Ok, lets say I have one user that registers to my site, user A belongs to org A and when they fill the form they say the are part of Org A. <span style="line-height: 1.5;">Or maybe they will have their own special registration page.</span> User B is part of Org B, when they fill the form they say is part of Org B. Or maybe they will have their own special registration page. A user that doesn't belongs to Org A or B will go to the usual site and follow the same registration process as any other general user. I want user A to see a special header, lets say a blue header, just because they belong to category "org A", and will see courses with prices specific for "org A" I want user B to see a special header, lets say red, just because they belong to category "org B", and will see courses with prices specific for "org B" And I want general users to see the traditional header and general prices. How can I achieve this? Thank you for your help! Eli~