Parent/child deals

Parent/child deals

I have run into scenarios where I might have follow-on deal to an existing sold deal and I would like to be able to consolidate them deals similar to how you can associate parent child accounts.  Is there a good way to do this activity?  I know you can clone a deal to copy data points, but I am really looking to show that I extended the initial sale into follow-on work with a new deal.  Thoughts?