You could always post-process the two files to merge them but honestly that would be piling one more hack on top of an already questionable heap.

The best advice I can give you here is to consider using some sort of template system for the output. That way you can construct your arrays of data within the program (see perldsc for how to manage a data set as a single item) and then just pass the assembled data to a template to format it how you wish in the output file. The venerable TT2 has much more functionality that you need for this one task but is worth learning IMHO as it will serve you well for solving the same general problem many times over.