Passing credentials
===

Dealer-->(Website 1 or 2)---->Dashboard<<--->> Website 3


Sorry for this crappy diagram, I would have inserted an image here, but I didn't know how to.

So,
--

    -- Dealer can login to any website (1 or 2) to see how many points he has got
    -- In order to redeem the points, dealer clicks on redeem button present on website 1 and 2
    -- When dealer clicks on "redeem" button, he/she will be redirected to a dashboard which will welcomes the user and tells how many points he/she has got
    -- Dashboard gets the total points from website 3 through REST calls and also to redeem points the dashboard redirects to website 3 which consists of items that user can purchase with those points (Website 3 is a reward site).
    -- the double arrows between dashboard and website 3 are REST calls.
    -- One more thing, the dealer only logins at website 1 or 2, from there the credentials keep on passing to dashboard and onto website 3
    -- dashboard doesn't need any login but website 3 does. dashboard is just an interface which welcomes the user and shows points (I know it has got no use, but it needs to be there.)


So, I just want expert advice from you on how to go about this project.
Thanks.