Conditional Formatting - Relative Reference - Icon Sets

Hi,

I'm working off of data in a single column.

I want to apply the conditional formatting (icon set) to the top 15 rows, depending on what the value of the cell is in row 16 - 30, or 31-45.

So for example

A1 = 1500
A16 = 1300
A31 = 1200

I would want the "green arrow" for A1 because 1500 is more than A16.

A2 = 1300
A17 = 1400
A31 = 1200

I would want the "yellow arrow" for A2 because 1300 is less than A17, but more than A31.

Now, I can do the above via the conditional formatting icon set currently. However, I want to copy the relative reference down the list and to the next 5 columns.

How do I do this relative reference conditional formatting copy?

Thanks.