An easy way to do it for the user account would be to place it into Workspaces and have the user click on the package and install it themselves. So doing would ensure the proper user context would always be there.
If you need to run it automatically, without user intervention, the only way I can think of doing it would be to push out a shell script that discovered the users on the machine and then executed the action based on each user profile. Something like:
userList=`dscl . list /Users shell | grep -v false | sed 's/_.*//' | sed 's/root//' | sed 's/Guest//' | sed 's/ .*//' | sed '/^$/d'`
for userName in $userList
insert your command here using the $userName variable