So if it is NULL you want it to appear in both group a and group B?
You will likely need to make sub-reports to accomplish this.
In the main report exlude all NULL records.
Group on 'Name'
suppress details
on group footer1 add a subreport using the same data source
link the subreport on 'Name'
in the subreport change the select statement to include the NULLS, something like:
isnull(table.NameField) or {?pm-Name}={table.namefield}
Arrange your data as you want in the sub report.