Shared Folder Permissions

Cant get me head around this one

I want to make a shared folder on the network, where all files that are put here become readable and writable by users from the same group. Am i right in thinking that if i used a umask to set file permissions to rw-rw-r-- then all files created would get those permissions? Thats what i want but only for files created in a certain directory. I dont want personal files in a users own home directory to be able to be written to by the group.

Is the only other way to do this with a regularly scheduled script to change permissions of all files in the folder to rw-rw-r-- ?
Seems a rather laborious way of doing it when in windows all you do is put files in the shared files folder and voila its done.

First you need to create a group just for that folder.
Then you can use it.

usermod -g group user (Changing their default group)
umask 0002 (for each user but this is changing their default) Means anything they create will have this group but as I cant go down one level into Desktop etc.

I cant see what they can do because they shouldn't be able to either because it will be a different group as in the one it sets up not the group you created.

Just make sure users folders aren't created with this group heading.

At least I think thats how its done....! Experiment and see what happens.