Linking Sub-topics possible?

No but here are some alternatives assuming MindManager 2012 is being used:

1. Link each parent topic to the same Outlook note. This will refresh each time the maps opened.
2. Use a floating topic with Relationship links to the parent topics.
3. Link the parent topics to a child map. Use Linked Maps View > Combine All to create a snap shot map with the child map content included.

The need for multiple parents can arise if you have a property that occurs on more than one topic, and have used the tree itself to visualise this. One example is visually mapping out tasks by person and by project area in the same map. Somewhere, you will need a task that belongs to two parents.

The Marker Index feature in MindManager 2012 is designed to overcome this, by creating lists of topics by marker, leaving the map structure free for use. The same topic can appear in more than one list in the Marker Index. So where you are using a child to parent connection (e.g. to show which person a task belongs to), use a map marker instead, and let the Marker Index pane show this topic in multiple lists.