Duplicates Highlight with condition from second column

Hello world,
so I have the sheet as seen in the attachment (I have included a picture in case one cannot see the attachment)
I have 2 columns, A for machines, B for products. I want to highlight those products that are created from both machines , so something like if duplicate and column A in the range of the duplicates contains both A1 and A2, highlight the range/cell, or something that identifies that.
Is that possible?
Thanks!
Example Pic.png

based on your sample you could use something like

C2: =IF(A2&B2=A1&B1;C1;COUNTIF(B:B;B2)<>COUNTIFS(A:A;A2;B:B;B2))

the initial test in the IF is just there to limit how many times you conduct the COUNTIF <> COUNTIFS test, to extent possible.