IPhone :: Delete Photos Selectively From Camera Roll?

I have thousands of photos on my camera roll. I do know you can select individual photos to delete off the roll and you can select more than one at a time but is there a better way? I keep hoping there would be a way to select groups of photos from my camera roll while my phone is connected to my macbook pro through iphoto. I was told you are only able to delete photos on your phone via your phone basically one at a time.

Info:
iPad 2, iOS 4.3.2, productivity tools and apps