shared databseconection (through static file system) across environments

Hi,

I'm very new to Kettle!

I have a situation here, i want to create database connection (holding data source connection details through file input) and that will able to access across all environments(Dev/QA/ST)

1. What property file should i configure to attain this solution
2. If that is doable by Variable? then i need approach of creating Dynamic variable
3. How do i access the proposed property file which is holding connection details through spoon environment

appreciate if anyone run through the same situation earlier and providing detail input to achieve the problem

thanks,
Sreeni