Bus Matrix - Business Process -to- Source System not 1:1?

We have a number of source systems that all do the same thing- receive loan applications. The reason for multiple systems is because some are web-based, some are for B2B, and some are legacy.

So, do we list three separate Business Processes on the Bus Matrix for each of these systems, or just one, because they all do the same thing- collect applications?

The purpose of the bus matrix is to model the fact/dimension relationship in the data warehouse. Unless you plan to have separate sets of fact tables for each source (NOT a good idea) then it should appear once.

Thanks. The reason I was unsure was that Kimball mentions 1st-level data marts usually are from a single source system.

It's best to avoid that, particulary if the information is basically the same. You may want to include a source system dimension (aka channel) in your fact table so that source can be identified.