reverse openid authentication

i have been working on an app just for managing users for all of the
other internal apps. to keep all of the usernames and passwords the
same across all of the apps, i used open id and built a server with a
few custom modifications.

everything is working great so far, but ideally i would like them to
log into the server first, and see all of the apps they have access to
and sign into them from the openid server. i thought about just
storing the session#create url for each app in my openid server
database and just sending a POST to the url with the users url, but
i'm wondering if there is a better way.

has anyone done anything like this before?