Shared element value for use in content items

I have 2 content items inside a custom WCM library. (IBM Portal)

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Both of which have an element, inherited from the Authoring Template they use.
The element is called URL and has a default value in the Authoring Template, of google.com.
If I change this value within Test, or within the Authoring Template after the 2 Content items are created it does not update the value used in both the Content items.

How could I setup such a variable/value? Which could be used in both Content items and always use the latest updated value.

Solution

Approach I went with was to use a component which stores the value.

Any other components/content items etc which need this value can import the shared component.