If I have an SF C# app connected to SQL Server and there is process in a business object that interacts with other business objects and changes data :

In my SF UI the interaction of the BOs is done in a winform code. 

The connections are made in the startup of the app. 

How would I call this same BO process from outside of my SF app ( or automatically run my SF app to invoke that process with no UI ) and take advantage of connections and bo interaction etc ? 

The idea is that a backnend process is going to run an SSIS package to get CSV data into a staging table ( one of the bos in my app ) and then bo logic is going to create or update reocords in three other tables based on the new staging records. 

I may also want to pass into the app the id of the staging record batch to process.

Suggestions greatly appreciated.