Combine all Multi-session files into a single file

[Clarity]

I am sure someone(s) has found a way to do this, so I ask for some guidance or your script.

I have, now, 5 multisession files on my HDD and they are found by taking the 3rd boot option from FD810 boot screen to gather them at boot-time and 2 save the current session changes, anew, if necessary, at shutdown. All works as expected.

Would anyone be willing to share their command or script to combine the 5 into 1, please? I assume you may be using an rsync or some comparable command.

And, no, I am not wanting to do a remaster. Merely to properly combine the dated session files on the HDD into a single session file.

Thanks in advance for guidance.