Unfortunately, you have posted to the Tips & Tricks sub-forum. This is a repository for articles on how to do things in PrE, and few will see your post here. Maybe our trusted MOD, Steve Grisetti, can move this out to the main forum, where more people will see it. Don't be surprised, if you see it moved.
Now, once you have edited your footage by subject, just set the WAB (Work Area Bar) over the segment for, say "Birthdays," and Share as DV-AVI (the DV part is important). Make sure that you check "Work Area," and not Full Project. You can then locate this file where you want it, and name it as required. That/those file(s) can then be Imported into a new Project.
Here's a look at the WAB in PrE 4. It's basically the same in PrE 8:
Good luck, and hope that this helps,
I appreciate the help
That showed me the way to solve my issue
Great news, and I see that Steve moved your post out to the main forum. He's very good at that. This allows more to see your post, and then they can offer other ideas for you. Most people do not frequent the Tips & Tricks area, unless they're looking for a solution to their problem. Then, they are not likely to hang around to help others, because they're busy with their own issue.