Hello Mbachand,
After testing this workflow, it appears that the second opened RWK file will write additional information in the file that will save the file but will also save the information from the other RWK file.
Example:
RWK-A
Original.DTM
Relocation.ALG
Relocation.ITL
RWK-B
Proposed.DTM
Relocation.IRD
When you open RWK-A it will open the Original.DTM, Relocation.ALG, and Relocation.ITL. You would then open RWK-B and it would open Proposed.DTM and Relocation.IRD. Upon saving the "Project" using File > Save > Project, it will save the RWK-B file with all the files (ie-Original.DTM, Relocation.ALG, Relocation.ITL, Proposed.DTM, and Relocation.IRD).