AutoCAD Visual LISP / AutoLISP :: Modifying A Replace Block Script

Is there a way to modify this script so you don't have to manually choose the blocks. Instead have it find all block names starting with "Supply Diffuser 24x24" and replace them with a block in the drawing named V01.
 
(defun C:CHANGEBLOCKS(/ printDebug ssAll ssAllTotal ss ssTotal ssCount ssCount2 ssTotal ssMainBlock ssMainBlock entListMainBlock ssBlocks entListBlock entListBlock2 entElementNewBlock entElementOldBlock entElementOldBlock2 oldBlockName) ;PROGRAM CHANGES MULTIPLE BLOCKS ;WRITTEN BY --- RAUL BENITEZ ;Command reference ;subst - returns a list with a new item substituted for every occurrence of an old item ;quote (or ') - easy way to make the string into a list. ;cdr - returns a list containing all but the first element of
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