This option doesn’t appear in the File > Share menu. Nor in the the Share icon (link). But it does in Preferences > Destinations: a Bundle.
What is it?
A Bundle is a group of share (export) destinations stored in a single place. When you choose File > Share a separate file is output for each destination in the bundle for each project or clip you are sharing.
For example, you could use bundles to simultaneously create:
Here’s how this works.
Go to Preferences > Destinations.
To add destinations to the bundle, drag an existing destination into it from the Destinations list (on the left), or select Add Destination and drag destinations from the area on the right into the bundle.
To rename any item in the bundle, select it and press Return (or click the name).
NOTE: To quickly make a bundle from destinations in the Destinations list, select one or more destinations in the Destinations list, then Control-click in the Destinations list and choose New Bundle from Selection.
Select each destination in the bundle and customize it with the settings you need.
OUTPUT
To share a project to a bundle, select the project, then choose File > Share > [bundle name].
FCP will ask you to confirm the settings for the first setting in the bundle, then use the default settings for the others.
Give the output file a name and location, click Save and Final Cut will output all versions in the bundle in the background.
Oh! And once you put a destination in the bundle, its name shows up in the File > Share list.
