How to white border cells using Stained Glass Filter?

Another way is a graphic style with two fills and a blending mode. Sample Illustrator file download:

Stained Glass White Border

You can change the fill colours in the Appearance palette.

You could make a mask using the same stained glass effect above the content and add a rectangle filled with another color below the content. Here's how:

1. Select your content
2. Go to Effect > Texture > Stained Glass... (apply the settings as desired).
3. Make a rectangle above the content that's the same size as your orininal content and fill it with white.
4. With the new rectangle selected, go to Effect > Apply Stained Glass (this option will appear at the top of the menu to allow you to apply the effect with the same settings that were just applied to your other content).
5. Select both the new rectangle and the main content rectangles.
6. Go to Window > Transparency and click Mask (The black cells of the stained glass from the top rectangle will mask the black cells of the stained glass of the main content and will leave gaps where the cells are masked).
7. Apply a rectangle filled with white or any other color color below the two other rectangles.