Two way sync on Microsoft 365 excel sheets between two excel documents

hi@mathetes fastly thanks for your reply, to answer your question why are there two spreadsheets designed the same way. Is that the fast spreadsheet let's call it LUCY is in the master file and the second one is an exact replica of lucy and we will call it lucy2, the reason for the duplication is because when I share lucy in the master file she will be able to see all the other documents in the master file and this are sensitive documents and each document contains details of a different person who works on it so to ensure she doesn't see I created a separate sheet called lucy2 and linked to lucy in the master file this way if I share lucy2 she will only see lucy2 and not lucy in the master file plus other sheets within the master file, that's why I needed a two-way sync between the two so that when I edit lucy in the master file the changes will be reflected on lucy2 and if she updates lucy2 the changes will reflect in the sheet called lucy in the master file.

what is the relationship between the two persons sharing this document, well the one editing the master file is the HR, and Lucy is a support staff in the company.
so if you know a way we can do a 2-way sync please assist because am stack I only linked one way from lucy2 to lucy in the master file using the copy and paste link method, so what lucy2 does is reflect on lucy in the Masterfile but i cant edit lucy in the master and what i do is neither reflecting in the linked lucy2 spreadsheet. kindly help