Convert color to grayscale. selected pages

Hey,

I know you can convert a pdf from color to grayscale using Preflight.

Is there a way to select certain pages?

For example: convert page 3 to 15.

I've got a pdf with links, so its hard to create a pdf with multiple documents.

I'm using

Adobe 9 pro

9.5.1

Thanks

Pieter Huyck