Hi Michael,
SAM's behind-the-meter financial models have a single load input, so it is not possible to model different load profiles without aggregating them into a single profile.
The "Electrical Configuration" section on the Detailed PV model's System Design page is just a grouping of inputs that determine the PV array's rated voltage (modules per string) and power (strings in parallel). Enabling more than one subarray is useful when groups of modules have different orientation, tracking, or shading, but I don't think would be useful for your application.
Best regards,
Paul.