I'll bet you can do it if you open the gmail app, go into settings and turn off the notifications.
I like the gmail app better than the email app, so I went in to the email app's settings and turned off the notifications for that. Surely you can do it in reverse.
My question is why you choose to use the crappy Samsung one? That was my very first change the day I got my phone. Only think I miss is the puzzle piece notification.