Merge multiple documents to an array in ultra pipeline

I have a similar use case where I need to insert data starting in row 6 of an Excel template file generated from Workday.  I need to preserve the formatting of the header rows in row 1-5.  I am able to read the Excel and then populate an output file by parsing the Excel input file , union of data and then the Excel multi sheet formatter to write the output.  The formatting is lost on those headers and I am told it needs to be retained.