Android : How to display 9 buttons in a grid layout with the same width and separated into 3 distinct groups by way of titles and spacing

The precise requirements for the layout as referenced in this image are:

• Each button has a common margin on all sides


• Each button must be the same width


• Each button must have a height equal to its width


• Top-left 4 buttons are in a group (Group 1)


• Top-Right 3 buttons are in a group (Group 2)


• Bottom-left 2 buttons are in a group (Group 3)


• Each group has a Title to it (TextView)


• Group 1 and Group 2 are separated by whitespace that takes up 1% of the entire screen width


• Ultimate i'd like this layout: http://1drv.ms/1qaE7sE