sum in dynamic range

HI,

I am stucked with calculating sumes in dynamic range.
Items in column A are copied from another sheet where are different ranges according with equip. categories (this ranges may vary). I want to make different sumes in column AB, according to different ranges as it is exemplified in the attached picture.
Any help much appreciated.
Best regards,
Moshul

later edit:
With help from a smart girl friend I solved the problem:

Sub test()
Sheets(1).Activate
LastRow = Range("AB" & Rows.Count).End(xlUp).Row
j = 0
For i = 5 To LastRow
If Cells(i, 28).Value = "Total" Then
Cells(i, 28).FormulaR1C1 = "=SUM(R[" & -j & "]C:R[-1]C)"
j = 0 ' j is row diff in dinamic ranges (diff btw first row and last row of the corresponding dynamic range)
Else
j = j + 1
End If
Next i
End Sub