Strongly recommend changing Workgroup to None as the best method.
Even generic resources should first be defined in the ERP.
Another thought might be to encourage users to always use the "Build
Team from Enterprise" option and select resouces from the ERP. Try to
discourage just typing in resource names - e.g. in Resource Names
column in the Gantt Chart view. Any mispelling gets entered in your
plan as a completely new resource with the default workgroup field set
to - probably "Default".
Also users often type a ;(semi-colon) instead of a ,(comma) when
assigning multiple resoruces and this can result in new resources with
the name "john smith;sam jones;tony green" !
Finally introduce users to the benefits of using the Assign Resources
dialog in MSP (2 faces on the toolbar). It makes assigning resources a
doddle and has fringe benefits when coupled with filtering on
availability etc. There's also a neat shortcut to Add Resources from
Project Server - although 2003 has a bug that closes the dialog when
you finish building your team
BTW: anyone with a solution to this little issue...? Cheers.