Make Buttons work like a RadioButton

Hi,

I have 4 Buttons, I want to make them Work like a “Radio Button”.

Like:
If i Click any 1 Button among the 4, i should be able to change its color and when i click on another Button the color of the previously clicked button should get its original Color and now the currently clicked button should change its color.

To make it More precise:
I have 4 buttons B1,B2,B3,B4: All this Buttons are “gray” colored, if i click Button(B2) the color of B2 Should change to “Green”, now if i click on Button(B4) the Color of B4 should change to “Green” and B2 should get its Original “Gray” Color.

Take a look at SelectionGrid and GUIStyles.