Conditional Formatting Custom Formula

Hello,

I am having some difficulties figuring out a custom conditional formula that changes the cells color depending on two conditions. One of those cells is a drop down list (E Select) and the other contains values that will be compared to values 300 and 500 to determine if it is less than or greater than (green if <= or red if >).

Condition 1: If twenty_20 is selected check values are <= 300 (make green) or > 300 (make red)
Condition 2: If twenty3_23/twenty5_25 is selected check values are <= 500 (make green) or > 500 (make red)

I would like to have a formula for a range of cells, but the formula that I came up with does not work for multiple cells since COUNTIF is counting the total cells that satisfy my condition, rather than looping thru each cell and assigning the correct condition. Not sure how to proceed. The formula is limited and works if a set up conditional formatting for each cell.

My problem is using the COUNTIF function: AND(ISNUMBER(SEARCH("20",$F$3)), COUNTIF($H3,">300")).

Thanks in advanced.