Need help with shipping costs not showing right

[cyberrick]

Website - 2strokeheads.com
Joomla version - 3.10
Virtuemart - 3.8.6

Can't update Joomla due to some extentions/plugins won't work with newer verions.

I have a site that has different shipping cost for different parts.  I need to have the checkout page show the total shipping cost based on each products shipping cost.

For Instance.

Polaris 800 CFI 12HP or 20HP Drop In Kit  - Shipping Cost = $32.00
250cc & 300CC Custom Billet Heads         - Shipping Cost = #20.00


Cart Shows:

Shipment

* Flat Fee - Shipping (Fee $32.00)
* Flat Fee - Shipping (Fee $20.00)

https://tinyurl.com/28ou9lyf

When two products are ordering with 2 different shippings costs, the checkout should only show & charge the higher of the two shipping costs.  How do I fix this?

Thanks.