HELP with Multi-Column Validation?

[Greg_Davis]

I have 4 columns that relate to each other row to row. This would also have duplicates, mostly starting in column A and less as you get to column C. D is an exact match to C.

I'm looking for in cell pulldowns for each and as you make a selection in A, it will narrow the search window (pulldown B) and so on to column C.

<TABLE style="WIDTH: 344pt; BORDER-COLLAPSE: collapse" cellSpacing=0 cellPadding=0 width=458 border=0><COLGROUP><COL style="WIDTH: 111pt; mso-width-source: userset; mso-width-alt: 5412" width=148><COL style="WIDTH: 74pt; mso-width-source: userset; mso-width-alt: 3584" width=98><COL style="WIDTH: 75pt; mso-width-source: userset; mso-width-alt: 3657" width=100><COL style="WIDTH: 84pt; mso-width-source: userset; mso-width-alt: 4096" width=112><TBODY><TR style="HEIGHT: 15pt" height=20><TD class=xl66 style="BORDER-RIGHT: #d4d0c8; BORDER-TOP: #d4d0c8; BORDER-LEFT: #d4d0c8; WIDTH: 111pt; BORDER-BOTTOM: #d4d0c8; HEIGHT: 15pt; BACKGROUND-COLOR: transparent" width=148 height=20>Category*</TD><TD class=xl65 style="BORDER-RIGHT: #d4d0c8; BORDER-TOP: #d4d0c8; BORDER-LEFT: #d4d0c8; WIDTH: 74pt; BORDER-BOTTOM: #d4d0c8; BACKGROUND-COLOR: transparent" width=98>Type*</TD><TD class=xl65 style="BORDER-RIGHT: #d4d0c8; BORDER-TOP: #d4d0c8; BORDER-LEFT: #d4d0c8; WIDTH: 75pt; BORDER-BOTTOM: #d4d0c8; BACKGROUND-COLOR: transparent" width=100>Item*</TD><TD class=xl65 style="BORDER-RIGHT: #d4d0c8; BORDER-TOP: #d4d0c8; BORDER-LEFT: #d4d0c8; WIDTH: 84pt; BORDER-BOTTOM: #d4d0c8; BACKGROUND-COLOR: transparent" width=112>Change Category</TD></TR></TBODY></TABLE>