WordPress Multi-Subdomain Integrated Login

To the point. I have 2 sites, one humanecologyforum.org (PRIMARY) and the other jobs.humanecologyforum.org (SLAVE)

They each have their own WordPress 2.1.3 installed, and are using the same mySQL database, with different prefix’s to deferentiate them.

I have figured out how to use the PRIMARY users tables to authenticate login’s on both PRIMARY and SECONDARY (after some trouble).

How do I make it so I can log in from PRIMARY and change to SECONDARY without needing to log in again?

I have read all the posts I could find on google and here on wordpress docs and support forums. I tried all the suggestions. I realize it is a cookie issue, but I can not track down what to do. For example, all the business about setting the Cookie Domain to ‘/’ root.

Could someone please give me a detailed explanation as to how I could accomplish this seemingly simple task. May I have just not seen a good enough explaination and need to it be done a little more thoroughly.

I would greatly appreciate it! WordPress rocks! it’s just annoying to have to login multiple times over and over…when everything should / could be seemless.

I also do know about wordpressMU and have used it, but it’s still a little too unstable for me unfortunately.

Thanks for your help, really!

-Chris