Now that we're focusing on costs we also need to be able to track
who's costs they are !. Resource should have a cost code/account 
code/cost centre (call it whatever you want) - which is a 
attribute associated with a resource.
<P>
Its not related to groups (though there is some overlap). I've
been on project teams where I'm on secondment and my cost code 
is completely different department. I'm in the development 
group but not paid by that group. I see Groups as ephemeral
organisations within a company thats formed to do a job on the
project and is only loosely associated with the payroll 
related accounting.
<P>
Ideally we create an Account dialog (like the group) and 
then in the resource have a picker (like group) which also 
has the default action like group does.

The Account stores ...
Account Name (text), Code (text), Manager Name (text), Manager Phone (text)
Manager email (text) and Default (checkbox).