Is it possible to add a lookup to a specific Manage Lookup Task?

Summary:

Hi,

Is it possible to add a custom lookup type to a specific task like "Manage Geography Lookups" or "Manage Location Lookups"?

When I view the task "Manage Location Lookups" I can see the option to add is visible, but it is greyed out - is this security? Or is it intended to prevent a user from adding a lookup type here? Is there any way to make a custom lookup type appear on the specific task page?

Thanks for your knowledge - here are some images for additional context