Producing two identical folders WITHOUT deleting anyhting?

[nbmenagerie]

I am sure this ia really simple. But after 65 years in IT (DP?) my brain is full up!
I cannot find an answer anywhere and I don't 'know' FFS well enough yet to know where to look?

I have two VERY large folders (>100Mb) with several 1000 files in each.
I will call them F1 and F2?

I can update F1 with additional files from one geographical location but not F2
I can update F2 with additional files from a different geographical location but not F1

I want to MERGE them WITHOUT deleting any files at all so that I get a complete and identical pair in two different places (They are actually on two different PCs in different countries and I can only access BOTH together when I am at my home/third location)

I tried doing various compares and synchonises but files always seem to get deleted in one folder or the other? [Only glad I kept copies!!]

EG?
F1 contains A + B + I +J + R + S (where the singles letters are files)
F2 contains A + B + I + K + P + S + Z (where the single letters that match F1 are identical files in both)

I want to end up with F1 AND F2 both containing A + B + I + J + K + P + R + S + Z (no file deleted)

Seems sinple but I cannot seem to work it out - I must be missing something simple!!

Flook

[blues12]

This setup should work for you: See attached screenshot.
Call up SyncRules (F8) and hover your mouse over the icons to make sense of it. To change an action, click on the green/blue arrow buttons.