If checkbox checked then data validation

Based on the description I would use the cell that's linked to the checkbox to "shift" a named range that populates the checkbox. You did not mention whether these were form controls or controls on the spreadsheet. The logic is the same the actual code would be different. Attaching a sample spreadsheet would both clarify the issue and encourage people to jump in. I'm not about to set up a spreadsheet from scratch to work the issue.