I know that the permissions listing are for user , then the group and the third one is for other users.
my example :
_rwxr--r-- tooth face file1.txt
_rwxr--r-- eye face file2.txt
_rwxr--r-- leg face file3.txt
groups included
tooth : face head
eye : face head
leg : body
Now, my question is : whether "leg" will have rwx permissions to file3 as it is not a member in group "face" ?