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There's no way that I'm aware of. That's one of the main purposes of using a custom launcher.
I saw someone post it here when googling: Hold both edges of homescreen to edit pages - Android Forums at AndroidCentral.com
Is it a Galaxy S III only feature?
Yes, it's very possible this is a TouchWiz feature.
Is there any tweak to do this without a launcher on the Market?
Okay, thank you for your help.My only suggestion is to try the TouchWiz launcher on your phone.
Galaxy S3 Touchwiz Launcher - Rescaled for Galaxy Nexus - Update: 6/6/12 - xda-developers
You're essentially using a custom launcher, but this one is not easily accessible or highly customizable.