Deleting records from the Backup eml file

I want to restore fewer files than I backed up. I can recognize eml's by thier name and want to delete them before I go through the 15 hour restor to my new googlemail account. Can I to that (delete the eml file)? or will it ruin by backup file or make restore impossible?

I have a 5.5 gig backup file.

cheers,

henry