Is there a way to copy paste all codes into a Portfolio sheet somewhere in QT's files?
From within the portfolio manager, export each of the portfolios you want to combine. The exported portfolio files are saved with a PEX extension. Make sure you give the export a name when saving because a default name is not provided.
You can now do a copy/paste between the exported PEX files. They are simple text files that can be opened with notepad. From there you can copy basically everything minus the first and last lines, then paste them into a new PEX file. To get this new PEX file, just make a new, blank, nothing in it, portfolio then export it. It's a little tricky to copy just the correct information. A few practice tries and you'll be a champ at it in no time flat. Once done, import the new PEX file that has all of the pasted symbols in it and you're good to go.