apart from NISHIL solution, you can write a custom decoder to write a logic for unzippin in it. Use flat file disassembler to to convert to xml and receive it inside ur orchestration
two component in ur pipeline will be
1) DECODER: for unzipping the files
2) FLAT File disassembler: To Convert into XML
NOTE: the main challenge in the solution occurs if the flat file u are dealing is very large size, which result in 3 times of size when converted into xml in disassembler.