Shipping calculation ok, display is not

This is a minor issue and doesn't affects overall performance, which is OK; However, it is very bad for the end-user experience.

I'm working on a site with a rather complex shipping functioning. I have several flat rate methods which are updated through rules following a variety of scnearios (shipping adress, weight, etc...).

I'm running marketplkace with the "Send payments to Main Store" mode, the one that suits my needs.

Marketplace does it job - and it REALLY helps - by separately applying all my shipping rules to every order.

However, the end-user (who does not know that he is actually doing several orders at the same time) only can see one out of the several calculated shipping fees, instead of the total sum

This is what the user sees

This is what the back-énd displays:

He or she might feel surprised - and even scammed - when he gets to the order review and sees its actual fees - double, triple or even more.

I've tried to figure how rules could possibily help to no avail.

A hacky solution is to "hide" with css the first estimated calculation and let people just choose their shipping service - and if they're not happy, they can go back and check other options. This is, however, a very bad practice.

Can anybody help me? Thanks in advance.