Matching Colors in Keynote

Is there a way to match a color on an object in Keynote? Something where you sample a color and then add that exact same color and shade to another object? I have photos in a Keynote presentation that are of the same subject and teh shade is off on a couple of the photos in regard to the others. Can I sample the shade I want and transfer that to the other photos? I know it can be done in Photoshop but I already have built the presentation wand would prefer not to touch up the photos and replace the work that I have already done.

Tks