Public Function BData(whichdata As Integer, anzdata As Integer) As Collection
Dim i As Integer
Dim v As New Collection
For i = whichdata To whichdata + anzdata - 1
        v.Add data(i)
Next i
Set BData= v
End Function

Dim out As Collection
Dim erg  As Variant 
Set out = Nothing
ReDim erg(b)
Set out = BData(a, b) 
i = 1
For Each erg In out
       erg(i) = erg
        i=i+1
Next erg