Pasting Metadata (Not Overwrite)

[Darius1968]

I know that if I have one file selected, and then perform a clipboard-copy, I now, can do a clipboard-paste attributes, which will effectively let me get metadata (EXIF, IPTC, GPS) and internal categories from the source file to the destination file(s).  Furthermore, I understand that if I have a provided option activated, which protects unwritten metadata, it does just that.  However, what if the destination file has some metadata that I don't want to be overwritten, but at the same time, I would like to merge some of the data from my source file to this destination file.  Is there explicitly, such a merge mode available, and if not, how can I achieve this end? 

[Mario]

The protection is only applied when IMatch imports data from a file, not when you make changes in the Metadata Panel or Keyword Panel.
If you copy/paste metadata in the Metadata Panel, the selected tag or all tags will be transferred. There is no way to apply merge options.

Either setup a metadata panel layout which contains only the tags you actually want to copy, or maybe use a metadata template which copies data from selected tags.

[Darius1968]

I think you've misunderstood my original post.  I'm not even involving the metadata panel, but rather, I'm effecting a copy on a source file, "A", then I select a destination file, "B", and do a "Paste Attributes" on that, at which point, a dialog pops up, giving me various options of transferring the categories, GPS data, XMP, and EXIF data, etc. 

So, it's now established that there is such a dialog that gives the choices of which categor(y|ies) of data to be transferred.  However, if I for instance, choose to copy-over all of the categories, the destination file is completely overwritten with the categories of the source file, when what I really wanted was for the destination file to keep those categories, already assigned, while accepting new & additional category assignments from the source file.  How can I achieve this? 

[Mario]

Ah, you using the Copy Attributes dialog. You did not mention that in your initial post.
You can perform similar operations via the Metadata Panel as well.
This dialog has no further options to merge/replace/append tags or other metadata. It only offers what is described in the help. No hidden features.

[Darius1968]

So, in that case, what to do to achieve the end of copying-over to the destination file, said data in a merge/append mode, instead of in a replace mode? 

[Mario]

This is something very specific you need there. IMatch offers no feature to merge arbitrary metadata. You can use a Metadata Template which offers some options, but not Copy/Paste Attributes.