I'm pretty sure there is a way to do it in a Smarlist, I'm not sure, but there is probably a better way...
Make it a View instead (under Audio in the tree instead of Smartlists). Searches you add to new custom views can do everything Smartlists can do, but you can also use the Panes (or tiles or whatever) to filter them on the fly.
So, do this:
1. Make a new view. ProTip: I have an "empty" view called "Mixes" under Audio in my tree, used like a folder (with Allow Tree Selection deselected), and then I put my fancy Smartlist mixes in there.
2. Add your Smarlist search with the shuffle to the Customize View -> Set rules for file display... dialog for your new view. ProTip: If you've already made a Smartlist that has basically what you want, you can copy and paste the rule using the import/export button in the Search dialog.
3. Add Year under the Show Categories part of the Customize View dialog. You can even add a few more useful ones, like Genre and Artist so you can filter by those.
And there you go! You have a smartlist that you can filter by year at any time on the fly.
Final ProTip: You can even make a Custom View that points to a Smartlist (or even manual playlist) as it's "source". So, you could just keep your existing smarlist (assuming you have one), and then in step 2 above, add the rule: Playlists Is Any Your Smartlist instead of copy/pasting the rules over. Any future changes you make to the Smartlist search automatically propagate to the View.
That's the way I do it now if I want one that I can use for things in MC like Syncing to a Handheld, which only work using an item under the "Playlist" part of the Tree.