Yep, you can do it with a one line action. You can automatically have the action pre-select all files by setting the appropriate checkbox in the Action Manager.

If you make it the Default Action (again in the Action Manager), it will be run automatically whenever you drag files to the dock icon.

You can also set an action to be run automatically when you save files in Preferences-Actions. The only gotcha with this approach is that files by default are only saved if something has changed. You can always force a save via Files>Save All Files>Save Always.

If you want to automatically export Media Kind when linked to iTunes you can specify this on the Preferences-iTunes-Auto Export panel.