Group Definitions

To add a group edit the /etc/group file

vi /etc/group

add

mygroup::223:des,jow,fred

mkdir /home/mygroup

chgrp mygroup /home/mygroup
ls -ld /home/mygroup

Give the group write permission
chmod g+w /home/mygroup 

Turn on set group id on mygroup so all files created in it have group id permissions  

chmod g+s /home/mygroupman chmod

ls -ld /home/mygroup

umask 2 (change umask to 2 to enable write for group automatically)