Is there a way to allow Zen-cart to handle multiple ship-by-weight tables within a single zone?

For example, if there are 2 couriers that ship to North America, both of which charge by weight, and both of which charge different amounts per weight (based on table lookups).

I've found I can simulate this by activating both the 'table rate' and 'zone rate' shipping modules at the same time, but this solution seems a bit awkward.

Thanks in advance.