Hi all zenners is there any way to achieve this ????

I am trying to add weight units to my items but this is not working for me as i have specific postage brackets e.g

1-25kgs would be £6.50 postage
26-50kgs would be £13 postage
51-75kgs would be £18 postage


so whether or not they order 1 item or 50 items i would like the delivery price on the weights as described above.

Is there any way to achieve this .

Many Thanks