SSO for drupal and lotus domino

Hi,

we have a drupal website running on Linux+Apache+Mysql+PHP and several other websites running on Lotus Domino. We need single sign-on for all those systems (the websites on Domino have SSO already). I know only about modules for sharing user login infromation (ldap_integration), but we need to allow people log in once and access all the sites. Also the access to particular pages, forums etc. should be restricted based on user access rights. For example only users from group A can post to forum FA etc.

I know Apache and Domino can be used together to get similar behaviour, but I think the access control is then based on (user,url mask) pair, e.g. only users from group A can access urls of the form /restricted-for-A/something.html . But then how to allow for some dynamic access control, e.g. to allow users to restrict access to their own forums to some particular set of usernames?

We would like to avoid modifying the drupal code (we are afraid of future drupal upgrades and need for additional changes) - is there some module available that we can use (I didn't find any) or do you have some idea?

If you wish to help us, please suggest some solution and price (e.g. "I would create a new module for $100" or "you have to buy that product for $100, then I would modify the drupal core to do SSO for another $100"). If you are able to estimate the time needed to implement the solution, please include it as well. I will discuss your offers with my chief and let you know. If you need more info, please contact me.

Thanks,

Petr