If you want to achieve this, the logic should be as follows :
echo Logs for user John; cat /home/john/bash_history > /root/userslog.file && chmod 700 /root/userslog.file # this will make it available only for root.
echo Logs for user Mike; cat /home/mike/bash_history >> /root/userslog.file # This will append Mike's logs, and leave a comment whose logs are these.
The same for other users. When this is done, just do : mailx -s "Users' logs"
your@adminmail.tld < /root/userslog.file
Something like that, this is what I can think of on the fly, certainly, there are more elegant solutions (I have something in mind).