How can I bend a Synth Chord progression ?

What synths are you using?  Do all notes need to bent by the same number of semitiones?  Does your synth respond to polyphonic aftertouch events.  Can you assign polyphonic aftertouch to pitch bend (I know the Yamaha XG standard can supports this) - this would be handy if different notes of the chord need to be bent my different amounts over the 10 seconds.

I have had a look at the MIDI Implementation chart for the s30 and unfortunately it does not support the receiving of polyphonic aftertouch events. So that method would not be possible.

If you have a chord where different notes bend by different amount, there is a work around that I sometimes use. (This happens a lot with pedal Steel guitars. The work around is to split the chord up into two tracks - one track has a one semitone shift and that other has a two semitone shift.  With the track that has the one semitone shift needs a command to change the pitch bend range to set it to one semitone instead of the default two.  On my Yamaha SW1000XG synth, it's RPN 0.  The s30 also responds to RPN 0 to change the bend range.

You have stated that "all notes would need to bend together" - I take that to mean that all notes in the chord need to shift by the same amount.  Because of that you can just use standard pitch bend events. 

Does the chord have to shift by the standard two semitones when the pitch bend is applied?

That method works absolutely perfectly with chords of a similar type, say from major to major or minor to minor.
 
If you wanted to go from e.g. major to minor you would have had to split it up and do the bend with 2 passes and combine the results.