Seperate installations sharing database but with different forum permissions at each

[Chunky Monkey]

Hello,

I am hoping somebody can help me out. I have several phpbb installations at different domain names sharing the same database. I changed their configuration files so that certain forums were hidden to unregistered/logged out guests at one domain but available to guests at a different domain.

I realize I would need a license for each vBulletin installtion I were to do this with since they would effectively be functioning as different forums, but can anyone tell me how to

1) Share a single database (same users, topics, posts, everything) among several different vBulletin installations at different websites
2) Make certain forums private at some domains
3) But make those same forums available to guests at others (different permissions for the same forums at different installations)

With phpbb it was a matter of "tricking" the software by hard coding the "auth code" for a particular forum in a particular installation's files. That is, at one domain, rather than letting phpbb pull the auth code from the database to determine whether guests could view the forum, I would provide the value myself hard coded in the file, so that every other installation would receive the value from the database and restrict the forum to guests, whereas the one whose auth value I manually supplied would display the forum to guests.

It wouldn't necessarily have to work as I've described above, but can anyone please tell me how to achieve what I'm trying to do with vBulletin?

To put it differently:

Site 1:
a - forum viewable by members, spiders, and guests
b - forum viewable only by members
c - forum viewable by members, spiders, and guests

Site 2:
b - forum viewable by members, spiders, and guests

Where b is the same forum at both sites. Basically it would be two or more installations of the Forum software sharing the same database, each at different websites, but only making available certain forums at each site.

I hope I've explained what it is I am interested in doing clearly enough. The fact that I've figured out how to do this with phpBB is what has prevented me from making the leap.

Thank you!