Horizontally Partitioned RDMSs

I am evaluating Tamino for use my organization…

I have a multitude of MS-Access databases spread throughout servers in my orgnization. The databases all have the same data model. Is there a way I can join the tables in these databases together to form one unified XML document that applications could query? I believe I need to define a constant for each data source so that if only one set of data is needed the application would use that constant/id.

I cannot replicate the data from the MS-Access tables because it is continously updated…

Is there a way to do this?