Need to auto-populate cells "N/A" when selecting from a drop-down list.

Hello Forum,

I have a need to auto-populate certain cells "N/A" when I select from a drop-down list. I know about VLOOKUP and the IF formula and have used it before, But I'm not sure if it will work in my scenario. I can't enter any formula in a cell where the "N/A"s go because depending on the drop-down selected, data may need to be entered into that cell (thus overwriting that formula).
I attached a snip of the spreadsheet I'm working on.
In reference to attachment... the drop-down in column C lists numbers 1-4. For example, if 3 is selected in C27, I need an N/A to populate in cells J27, T27, P27, V27.

Is there a way make this happen? Again, I can't enter a formula into the cells that need the N/A.