To create multiple output files using the Boston Code Generator, here is an example to model off:

Have a data access template.

Here I've called it DAL, on the left hand side explorer. The header name is dal(). And in the header definition is a for expression returning based on table in the for variable.

 

There's another template I've added (right click Package -> New -> Template) called UI, named ui().

It just outputs a single file.

 

Then call dal() and ui() templates in main.

 

It outputs multiple files based on tables for the DAL template, and a single file for the UI template.