Single Shipping Cost For Orders With Products From Multiple Vendors

Dear CS Cart Community,

In cs-cart multi vendor, when a customer buy several products from multiple vendors, the system calculate several shipping options assigned to product's vendor and sums shipping costs. How can i receive the shipping cost once as i will be shipping the items from my warehouse (vendors will not be doing any shipping) therefore i need to only take the shipping cost once from the customer? Basically it should look like this,

Product 1 from vendor A - $200
Product 2 from vendor B - $200
Product 3 from vendor C - $200
Shipping - $25
Total - $625
I'm really struggling with this, can anyone suggest or help how this can be achieved ?

It is not possible out of the box. Additional code changes are required