Not everything in a planning sheet is a number that changes every month. Owners, dates, statuses and names belong to the row, not the time period - and that is what a visual column is for. We tidy the view first (column grand total off, filtered to 2026), then add a Person column renamed to Country Manager, with input allowed in both read and edit mode. Assign a user to China, copy that name to all rows in China, and confirm it does not bleed into any other country.