Watch the Sus4 Connection online guitar lesson by Brad Carlton from Chord Studies: Slash Chords Vol. 2
Here we have four voicings of a sus4 chord with an A in the bass. Our first voicing of Asus4 has the A on the twelfth fret on string five. Move everything down one fret and bring in the second finger for the Gsus4/A. Then we move down and switch fingerings to get the Csus4. Notice we then move the top voicings up a whole step and change our fingering for the Dsus4 with A in the bass. You could try it with the fifth string open for a different sound.