Hi Roger, I asked this question before as I would also find it very useful.
Here was my post: https://success.clarizen.com/hc/en-us/community/posts/203989248-Attach-risks-to-a-project-template
I didn't use a workflow rule to create the risks and link to the project as I had too many, but it should work.
Make sure you update the field "Resolved In Project" ($PlannedFor) on the the risk to the new project - perhaps use a variable.