Say I created two tablesin Microsoft Excel. In a cell above the two tables i
insert a value. To use table 1 you insert the letter (a) or to use table 2
you insert (b). How can I do this?

when i insert the letter (a) I want table 1 to be highlighted yellow and
table 2 to be highlighted red. Also i want table 2 to be locked when i insert
the letter (a). The same goes for the letter (b) but vice versa. How do I do
this?