conditional match first 2 letters of 3 cells

What would be a conditional format formula that would return a result based on 3 cells in a row of 10 cells all having the same first 2 identical letters? Example, if the words in the 3 cells all start with EV, the whole row would stay unaffected, but if one of the 3 cells had a word that began with something different, say EE, then the row would be highlighted in red. I have figured out how to match two, but cannot get three. I appreciate your consideration, Gary