Need help, not sure if this is possible.

I have a table which pulls data from an external query.
Two columns pull in a production order number and then the scheduled end date.
Every time I refresh the query, it updates the table with live scheduling info and that end date moves in and out.
I would like to keep a new table that adds a new production order to the list everytime it first appears (when the planner first schedules it) and then record the end date. I always want to be able to see the original end date, in addition to the query of where it may happen to be upon a refresh.

Maybe some formula to look at the table of existing production order numbers, then scan the query table for anything new. If a new prod number is found, then add it the new table and record the end date in the column next to it.

Thank you all for any help you may be able to offer.
Rob