Mirror source drive to two backup drives how ?

[DBenz]

Hi, New to Free File Sync.
I have D data drive and its backup exists on two other drives O and a usb_HDD_018 as not all of D will fit on O , as O has data to keep I have had to delete from D to make space, so overflow is to the usb _HDD_018.
How can I get it to show me :-
1. what matching folder names exist and which drives they are on ?
2. what folders and files are unique to D
3. Backup D (mirror to O and usb_HDD_018 ) at same time, by which I mean it copies the data to either drive at the same time in that copy action.

If I were to compare D to O it would show me the folders that were not on O, I could then select them and copy contents to the usb, if I didnt want anything deleting from the usb, else I would use Mirror to usb. Would it do this as I am not aware it will copy multiple folders to same multiple folders on another drive, one has to do it 1 folder at a time which is impractical.
Could it in fact auto select the folders by matching addresses or do I have to browse for the multiple folders ?
Unless though it allows multi selection its going to be one at a time.

I might have it suggested to me to place all my folders into one, on D and on O then move them back out again, to have to do such can cause confusion, even a slight risk of data loss when the contents are many Gb.
The other day the drive I was doing this from had an I/O error (unable to be written to) so any movement wasnt possible anyway !

Cheers
DBenz

[xCSxXenon]

You are trying to do two syncs in one and that can't work. You will have to set up filters over two syncs to split up the content on D to the two locations. Splitting a backup to two locations is a problem because of the breadth-first sync FFS performs.