Controling sheet navigation.

[Jay S Emmet]

I would like to control the navigation keys on a worksheet so that if any of the first row of cells is selected, the user will be able to use the tab or arrow keys to navigate to the left or right, but if they press enter they will be taken to the next cell directly below the one they are in. After ariving at any of the second or third rows of cells they could only navigate up or down, reguardless of the key used i,e, "Enter" or "Tab". Upon arriving at the fourth row of cells, they would be taken back to the top row and the next column. (See Example below)
Does anyone know if this is possible?

Book2
	A	B	C	D
1	Modified Tab/Enter Order and Selection
2	1	5	9	If any of these cells are selected, you can hit TAB to go to next column
3				or hit ENTER or DOWN to go to next cell in column.
4	2	6	10	If any of these cells are selected, you can only go Down or UP to the next
5	3	7	11	cell in the same column.
6	4	8	12	If any of these cells are selected, you can only go UP to the previous cell
7				in the same column, or to the TOP cell in the next column.
Sheet1

EDITED to fit image - Admin