forms - Merge multiple table entries

I am building a widget to merge Records. Lets say, this table is information on Cars. There are variable/data points like VIN, Milage, etc..

Now, there may be more than one entry of the same car in the system and I want to allow users to be able to merge these. Currently we indicate the duplicate entries but we only allow them to merge 2 at a time.

My questions are -

1) How do I let users merge more than two records in this screen? 2) how do I implement "Select all from Record 2" kind of an approach. I was thinking of a radio button in the Column Header as well.

I am skeptic of using a horizontal scroll bar. Yes there may be a vertical scroll since there will be many rows. So I would make the first column sticky and then have both scroll bars. But I know there may be a better way of doing this.

I am also thinking of a 2 column approach like this:

Can there be possible usability issues with the dropdown approach?