Specifying whether a set of combo boxes will enter data to a new row?

[BPSJACK]

Hi there, I have a basic userform with three comboboxes (WIDTH1,LENGTH1,HEIGHT1) . The users selections will be be sent over to the next empty row in sheet 2.
I want to be able to have multiple sets of 3 comboboxes (in one userform), whereby data from each 'set' of comboxes will enter to the next empty row in Sheet 2. EG WIDTH2,LENGTH2,HEIGHT2 will go to a new row, and WIDTH3,LENGTH3,HEIGHT3 will be entered to a new row and so on.

Any help as to how I might accomplish this would be much appreciated.
Here is my current setup:

Private Sub cmdAdd_Click()
Dim iRow As Long
Dim ws As Worksheet
Set ws = Worksheets("SHEET2")

With iRow = ws.Cells(Rows.Count, 1) _
  .End(xlUp).Offset(1, 0).Row
  
ws.Cells(iRow, 1).Value = Me.COMBOBOXWIDTH1
ws.Cells(iRow, 2).Value = Me.COMBOXBOXLENGTH1
ws.Cells(iRow, 3).Value = Me.COMBOBOXHEIGHT1

  
End Sub