How to display the sum of a task custom field in a project report

[SarahFaure]

Is there a way to create a column in a project report that sums together all of the values of a task custom field?

We added "copy hours" and "design hours" custom fields to tasks, and I want to see a report that sums the copy and design hours for each project without having to pull a list of every single task for that project. Any ideas?