Conditional Formatting - multiple criteria

Search COL A - if an "O" is found, change all of the values in COL C to RED
if they match the same value as COL C of the "O" record

Example:
x - Jim - 5
O - Mike - 4 All 4's in COL C would turn red (Mike & Hank)
x - Pete - 3
x - Hank - 4

Attached example.