Yes. Take the following file as an example:
Code:
-rw-rw-r-- 1 someuser somegroup 81743 Oct 8 00:45 index.html
The file was probably created by "someuser", who is the owner and is able to read and write the file. Any members of "somegroup" can also read and write the file. All other accounts on the system (including the one that your web server runs under) are able to read the file.
If you want "anotheruser" to also be able to modify the file, you can add that account to the "somegroup" group with the
usermod -a -G somegroup anotheruser command.
If you use the
setgid bit on a directory, all files created in that directory will inherit the same group. This is handy as you then don't have to manually set the group on new files to "somegroup" all the time.