Salesforce.com driver & multiple instances

Hi all,

I would like to implement the user provisioning in Salesforce.com using the corresponding driver.
However, there is one Salesforce instance created for each work location.
It means one login name for each instance.

Do you think it is possible to create just one version of my driver connecting to the right instance regarding the user location?
Or do I have to create one version of my driver for each Salesforce instance? (=> more difficult to maintain)

Thank you in advance for your reply!