Altarum --
Yes, you can assign a single risk to multiple tasks. When you create a new
risk, you will see that there are blue links at the bottom of the page
listing items such as Affected Tasks, Triggers, Mitigation Tasks, etc.
Select one of the blue links as needed and you will see the Link to the
selected tasks dialog. Select the All Tasks filter at the top of the
dialog, then select the checkboxes for the appropriate tasks, and then click
the OK button. Hope this helps.