Not just a plugin. It's a built in feature.
This kind of stuff is handled by the trax editor. Trax provides a way to organize animation segments and blend seamlessly between them. It can also store poses. The animation snip data is kept in a separate archive window called the visor.
I'm a novice with trax myself, but I'll wager that you can probably export/import animation/pose nodes just like anything else. I'm kind of in a rush right now though, so I'll have to let someone more qualified fill you in on the details.
Only one word of warning: your character needs to have a character set to use trax. If he doesn't, you are going to have to be very careful to set up his character set exactly the same in both scenes, so that you don't run into any trouble transfering the animation. Trax provides ways to transfer data between dissimilar character sets, but it's messy....