Archive old holdings

•I have equities going back to 1993 in Sharesight.
Some (not all) of those equities have been fully sold and are no longer relevant for tax purposes.
Nevertheless I want to be able to run “Performance Report” for all holdings including those closed portions of holdings which still have some parcels remaining.
As a workaround I run the report with “include closed” but have a label on those equities that have zero units now. Thereby I can run the report just for existing holdings but include those bits that have been sold without including Equities that have been fully sold.
I would very much like to be able to archive (or move to a pseudo “history” portfolio) all those equities that now have zero units held, while retaining those that still have some units (including keeping the closed portions of those holdings – for full history reporting).
For my purposes, I’d probably archive anything that has been fully closed for more than 5 years.
Another way around this would be if Sharesight allowed moving of holdings between portfolios - then we could create our own “History” portfolio and move those holdings out of our regular portfolios.