Sync column in two different spreadsheets from imported data

Question

I have a private spreadsheet and a shared spreadsheet with data imported from the private one. I want users to be able to make changes to the shared spreadsheet, that will reflect on the private one. For example, I would like users to be able to uncheck column A cell 1 here https://docs.google.com/spreadsheets/d/1JX6XFGJksanTPIrN7oqVf1iDDIxXeFDG8Xq3iHXGEBo/edit?usp=sharing and have the change reflect on the private spreadsheet here https://docs.google.com/spreadsheets/d/16FJzFqWkyN9vy2E3IFpaifybwfdoq-iLj_qKZsnQau8/edit#gid=0

=IMPORTRANGE("16FJzFqWkyN9vy2E3IFpaifybwfdoq-iLj_qKZsnQau8", "Sheet1!A1:U1000")

I expect to be able to change data in shared spreadsheet and have it reflect on the private spreadsheet

Answer 1

IMPORTRANGE and all other formulae are 1-directional which means that your issue can be solved only this way:

the private spreadsheet consists of green cells with the red formula:

=IMPORTRANGE("ID_of_shared_spreadsheet", "shared!B1:C")

and shared spreadsheet consists of green cells and this red formula:

=IMPORTRANGE("ID_of_private_spreadsheet", "private!A1:A")