Dropshipping in Australia (How to match suppliers freight costs)

[ainsbee]

Hello everyone, I'm asking for some help, please.

What if the suppliers (multiple suppliers) ship the products for us, their products are industrial items so they are large and heavy (10kg to 120kg with the dimensions of  190cm x 130cm x 63cm).

How can we match or how can we calculate the cost of freight to match theirs if they are using their own carriers, not just 1 but many. And they only ship within Australia. We have Australia Post but the calculation is not that accurate.

Are there any shipping calculators that I can use so the shipping cost will be automatically calculated when checkout? 

Thank you.