This script is a modified version of one of the M.E.S.A. bundled scripts. It assumes M.E.S.A. is running and that an existing program and a list of samples are selected within the M.E.S.A. "Memory" window. It uses a program selected in the "Memory" window to define a series of chromatically mapped keygroups, each of which plays a sample without looping them in playback.
This was one of the first M.E.S.A. AppleScripts I "messed with" and I tried to comment the most significant lines to make it easier to understand. I have since learned to use AppleScript "handlers" which are more modular and easy to read.