Connect to Mulitple Databases - PHP/MySQL

I need to modify an existing script to connect to multiple databases. Basically, when a user logs in, the script needs to query each databse until it finds the user. I need this setup to query 3 databases now but I will need to expand this in the future. Please do not bid on this unless you are absoltely certain you can complete the project. This is my second attempt to get this project completed and I am already behind my time frame because the intial provider was unable to complete the job. Ideally, I would like to find someone who is available to start this project immediately and complete it within a few hours.