IF/THEN Statement in Access Database

Material Number1 Material Description Cat Number
My table is attached.

I have Material numbers that are the same but the Material Description and CAt number are different. The Material Number is my Unique ID, therefore, I need to elminate one. I would like the formula to choose the second row of all the duplicate Material Number1. There can be another column that is labeled "Yes" or something to that fact so I know which ones to keep. The problem is that both Cat Numbers is found in the Material Number1 name. I thought about saying if the CAt number is in the Material Number1 than "yes", but they are both in there. I would prefer this to be in access. So, if a formula won't work, possibly a VBA code.

Is this confusing?