I've been having much success with this and thought I would share it since it took me awhile to work through. I create a policy which first delivers one copy of the file to a central location on the Mac (in this case, a folder named /TEMP). Setting up the following shell script to "Run After" causes that file to get copied to each user's private documents folder :
#!/bin/bash
myUSERS=$(ls /Users)
for i in $(echo $myUSERS)
do
#
# This will copy a text file from a TEMP folder into each user's Documents folder
#
if [[ $i != "."* ]]
then
cp /TEMP/MasterTemplate.txt /users/$i/Documents/Template.txt
fi
done