Groups: Howto and New?

[J Horacio MG <homega@vlc.servicom.es>]

I have a directory within /home (ok, probably not the right place for
it) which I use to store several documents and other stuff;  I'd like to
be able to read and write to it just from my user and from root, so I
thought of making a new group and changing that directory and files group
permissions to the newly created group.  Is this a right way to do it?

Also, how can I have information about groups (other than the one
provided in /etc/groups)?

TIA
-- 
Horacio
homega@vlc.servicom.es
Valencia - ESPAÑA