Question on how to implement identification of set in R
===

I have 2 variables that, when combined, uniquely identify a product (barcode id and catalog descriptions). Barcode numbers and catalog descriptions have drifted over time, but not at the same time (e.g. barcode value for one product changed in May, then catalog description slightly changed in December). I would like to create some kind of object to identify these drifts (e.g. when barcode value xxxxxxx, connect all catalog descriptions, then with all catalog descriptions, connect all barcode values, then continue until no more matches).

Any idea how to implement this?