How to Integrate two Dolphin sites together?

Hello i been thinking about this for a while and had a few ideas but i wanted to know for sure how i could intergrate one Dolphin site from the same server (It's a freinds site) to using the same user system and profile system as mine.

Basically my friend owns reseller account on my server but we are going into bisnuess togeather and i going to help him with his clients and etc, but we want to have the same user database so users can just log into both sites but also like when the users submit a blog it will display on both sites home pages. But when a user submits some audio or a video or etc we don't want it to display on his site but just mine.

I hope this is enough info, if anyone had any ideas it would be great, I got an idea myself but i want to test it before i share, i don't think it will work though.

Thanks. 

Sorry about spelling in a bit of a rush.

This is the closest you'll find to that on the Boonex market: http://www.boonex.com/m/Cross_Database_Profile_Synchronization

According to the description it has a tool to synchronize all profiles so you can add as many sites as you want after installing this mod, or you can synchronize existing ones.

Good luck!

Yeah that mod is great I remember suggesting it with my client having three site integrated with a link on top menu redirecting to other site with same members, mods and files. 

Thanks for the reply's, and sorry for the delay i had my internet cut for a while.

But sadly at the minute I do not have the money to buy that :(, looks like i going to have to figure it out by myself I am pretty sure i should be able to do it it, and if i succeed I will post a tutorial on how to do it :).

Thanks anyway and if any can suggest anything else, your always welcome here xD.

Thanks 

klimyriad