Here's Schlabber's take on this in case you want to save 2 characters at once.

'A complete-scene-character file (or adding 2 figures at once)

Quite easy. Just take a *.pz3 (this is the Poser-Data-Format), rename it to *.cr2.
Copy it to the character folder, go back to Poser.
Open the scene. Save it in Poser under a new character-name (to have the preview-image).
Open a file editing-tool (Windows Explorer) delete the 'new-saved' *.cr2 and rename the 'new-saved' *.rsr with exactly the same name then your old *.pz3 (now it is called somewhat.cr2) - finished.
Now you can quickly add this scene without openning it!

Example 1:
Name of PZ3: scenea.pz3
Rename scenea.pz3 to scenea.cr2
Copy it to runtime/libraries/character
Go to poser and open this *.cr2 - you'll notice there's an image missing
Save the scene under another name (scenea2).
Go back to the windows-explorer (alt+tab) and refresh it (F5)
Now delete scene2.cr2 and rename scene2.rsr to scenea.rsr '

OOps, it just occured to me to wonder whether I'm allowed to copy this verbatim into a forum...?

At any rate Schlabber's site: www.schlabber.org

Great poses.
Cheers,
Masha