I made a video to show a quick & easy way to get this:
I used mission 16 'The old & the new' - cleared the starting area, everyone picks up a dead body (Hector carries 2) and stands in a bush.
Enter showdown mode by pressing
Cycle through each character using
and drop the body using
Then quick-save and press
to make them all drop the body.
Reload & repeat for 6 x bodies at a time.