Sometimes, when it comes time to manage computers, IT and Accounting don't always see things eye-to-eye. A department based collection -- while may be important for Asset Management -- may not meet the needs you have for delivering software.
A good example is in our organization where we recently migrated from Novell ZENworks to a fully Microsoft environment. Altiris has been a great help in getting this done, but our department information didn't match up with that old NDS tree. Luckily, Active directory did. By using the following query we were able to map computers to a collection by using the Owner's Fully Distinguished OU name.
select DISTINCT r.[ParentResourceGuid] AS 'Guid' from ResourceAssociation r inner join Inv_OU_Membership uo on uo.[_ResourceGuid] = r.[ChildResourceGuid] Where r.[ResourceAssociationTypeGuid] = 'ED35A8D1-BF60-4771-9DDE-092C146C485A' AND uo.[Distinguished Name] = '<OU INFORMATION HERE>'
When finshed your OU should look something like: 'OU=Users,OU=Container1,OU=container2,DC=Domaincontroler,DC=COM'