How to join/merge/union 2 tables so that new rows from one will be available in the other

I have a table of devices:

NET_TABLE: vendor - model - location - name - contract - owner (plus about 30 more columns)

The ops team copies that table removes some columns and creates more columns:

OPS_TABLE: vendor - model - location - name - notes - engineer - customer (plus about 40 more columns)

Whenever I add a new device (row) the ops team has to copy the new table and go thru a cumbersome process to keep their data.

This seems really inefficient. I don't really want to populate my table with their columns.

I'm thinking there must be a way to "union" or "join" my table with their table to pick up only new "vendor - model - location - name" rows, but I can't figure out the syntax to do it.

"union" seems to want a matching number of columns, and "join" seems only to find commonalities.

I can't seem to wrap my head around how to solve this, but it seems like a really simple problem.

SteveJ