In your query criteria try
IIf([Forms]![Form_Name]![Option_Group]=-1,-1,IIf([Forms]![Form_Name]![Option_Group]=0,0,-1))
or
IIf([Forms]![Form_Name]![Option_Group]=-1,-1,IIf([Forms]![Form_Name]![Option_Group]=0,0,0))
ie. in the first criteria line put line one of the code and in the second line...