Hi @dcshanno,
Building on the sage advice from @Sven-iX, I invite you to consider this Going the Extra Milestone advanced technique to get what you need with minimal disruption to your existing Workplan structure(s).
If you like the latter, you can templatize it, going forward.
Going backwards...
If you want to take it even further, you could then also use our Sync Template solution to update existing Projects with those updated Template changes now, and thereafter, in a continuous improvement manner.
Regards,
Doug