Grouping Issue in Reporting Services

I have a report that needs to be grouped by Department Name. I created a group and Grouped it by DeptName. However, as it is to show all the details per group...it shows that but doesnt make the group distinct.. Here is an example

THIS IS NOW!:


Group 2
              Name  Num blah blah
Group 2
              Name Num Blah Blah
Group 3
              Name Num Blah Blah


Its suppose to SHOW:


Group 2
              Name  Num blah blah
              Name  Num blah blah
Group 3
              Name  Num blah blah

I tried putting the Name Num details group to group on DeptName ( Group 2) and its still doing it. The name field has a code that makes sure it has a distinct name per group.. which might be interefering.. here is the code

Function IsEqual(name1, name2)
 if(name1 = name2)
  return ""
Else
 return  name2
end If
End Function  

=Code.IsEqual(Previous(Fields!LastName.Value & ", " & Fields!FirstName.Value),Fields!LastName.Value & ", " & Fields!FirstName.Value)


I hope that isnt interfering with making a distinct group. Let me know what i am doing wrong as i think its a easy fix and i just am braindead right now. Thanks