EXCEl - Find Conincidences on a Matrix

Maybe someone can help me to use a formula for the following issue, I have tried to think how to do it, but I dont see it...

I have one sheet with 2 Columns A Spare_part_code and B Part_type, being A alphanumeric codes, and B, just a letter from A to E. (we assign the importance f a part based on the letter, being A most important and E less important) Then on another sheet, I have a list of repairs, one per line that have in lines from G to X the parts used on that repair.

I would like to, per repair, have a formula that search among all the parts used on that repair, and return the level of the parts used, but only the Letter of the most important part, for example

For repair XXXXX I have used 10 parts, and all of them are E type, except one wich is B, so In this case I need to show B on the result For repair YYYYY I have used 3 parts, all of them A, so I need the formula to return A

I hope I explaines myself properly...

thanks!