support for multiple database session

Hi all,

I am working on a rails project. First I am giving a brief of what it
does then I will tell what are issues I am facing.

This project is basically a reporting tool that gets data from database
and generates report. I have different databases for different products
with same structure (schema) for all. I want to have a drop down menu on
the homepage where user can select which database he wants to connect
and generate report for the selected database. I am connecting to
selected database manually in application controller and using this as
before_filter in application.rb.

Problem is that user can select any database while logs in. When two
users log in selecting different databases. The user who logs in later
only database session for that user sustains and data from other
database no longer accessible to user logged in first. Rather he also
now gets data of 2nd database.

I must implement it correctly. Please suggest me how it can be done. I
have 5 such databases to connect dynamically with each user always gets
data from selected database.

Thanks a lot,
Nitin.