Is there a way to programmatically change the import sql of a table?

Because of the lack of multi-tenancy support in PowerBI, I need to deploy a report per customer.  Each cutomer gets a seperate copy of the pbix with their own data in it.  I assume this means I need to filter on CustomerId in my import sql (unless there is a better approach).  I can't see a way to change the sql programmatically.  The REST API doesn't seem to have that provision.

I could really use some help on this one.