See the "Multiple items per condition" item under the "Special merges"
section of fellow MVP CIndy Meister's website at

http://homepage.swissonline.ch/cindymeister/MergFram.htm

Or you may be able to modify the following macro to do what you want:

' Macro created by Doug Robbins to create multiple items per condition from
a directory type mailmerge

Dim source As Document, target As Document, scat As Range, tcat As Range
Dim data As Range, stab As Table, ttab As Table
Dim i As Long, j As Long, k As Long, n As Long
Set source = ActiveDocument
Set target = Documents.Add
Set stab = source.Tables(1)
k = stab.Columns.Count
Set ttab = target.Tables.Add(Range:=Selection.Range, numrows:=1,
numcolumns:=k - 1)
Set scat = stab.Cell(1, 1).Range
scat.End = scat.End - 1
ttab.Cell(1, 1).Range = scat
j = ttab.Rows.Count
For i = 1 To stab.Rows.Count
   Set tcat = ttab.Cell(j, 1).Range
   tcat.End = tcat.End - 1
   Set scat = stab.Cell(i, 1).Range
   scat.End = scat.End - 1
   If scat <> tcat Then
       ttab.Rows.Add
       j = ttab.Rows.Count
       ttab.Cell(j, 1).Range = scat
       ttab.Rows.Add
       For n = 2 To k
           Set data = stab.Cell(i, n).Range
           data.End = data.End - 1
           ttab.Cell(ttab.Rows.Count, n - 1).Range = data
       Next n
   Else
       ttab.Rows.Add
       For n = 2 To k
           Set data = stab.Cell(i, n).Range
           data.End = data.End - 1
           ttab.Cell(ttab.Rows.Count, n - 1).Range = data
       Next n
   End If
Next i