Conditonal Formatting a Cell Based on Other Cells

Here's what I got.

I'm doing a Comparison of Price quotes from some different vendors and I want to highlight which one is the lowest.

4 Rows with Totals
The Cells are B21, B43, B65, B87

I need each value in each location to be compared to the other 3.

The other thing is that I also C through V that need the same thing.

Thanks.