How To Integrate Many Joomla Installations In One Site?

I want to make a website which has 5 different joomla installations on the same server. Each need to have all users in common but with different fields in table.
For example:
If I call the installations as joom1, joom2, joom3, joom4, and joom5, then users who register from any of these installations have say 10 fields [...]

Joomla - Can I Create As Many Websites (template Managers) As I Want?

I am a curious about these IT things and like to learn a lot by myself, mainly in the internet. But of course, sometimes I need help from the experts.
So, the question is: I already have a proper business website done in Joomla. Is it possible to create other websites (as many as I want) [...]

How Many Templates Can I Upload On A Joomla Website?

As many as you want.
Regards,
Glenn
www.webjutsu.com

There A Joomla Gallery That Will Have Many Albums For Different People And Supply A Password Download Option?

I want a page that supplies various galleries that is password protected for particular albums and will allow the person to download photos if they wanted to.