Copy foreground / paste background

Hi~, all.
Can I copy foreground and paste into background with multi glyphs?
I found the discussion on this issue, and I wonder if there is a solution or helpful idea.

What do you want to do exactly? Copy the foreground into the background? Try Selection to Background (Cmd-J) or Assign Background.

Sorry for strange describing…; / I would like to put selected glyphs’ foreground into target glyphs’ background without changing target glyphs’ foreground. As it was already discussed in this forum, I tried to find out the solution but I couldn’t.

Within the same font? Probably best with a throw-away file, in which you paste the glyphs and rename the to your target glyphs. Then, you can assign the background with the menu command of the same name.