Shipping Zones Australia by Post Code

[Big Ben]

I am just commissioning new site on 155 Responsive - so far it is working fantastically - Thanks to everyone at ZC involved.
We ship by various couriers nationally throughout Australia 1 to 500 kilo loads and are charged per Kgm per destination defined by Postal Zones in Groups. Depending on Zone can vary from $0.50 to $4.50 per Kgm.
Previously I have used zone tables with zones defined by State - this is too limited.
We need to use zones defined by (groups of) Postal Zones.
Do not want to use available "online connection" to freight company sites as we use several carriers for commercial reasons.
Australia has some 3000 separate Postal zones. In practice we could group these to total around 20 to 30 zones.
Ideally we need a method which quotes Price calculated by: Weight (in segments as per current tables is OK) x $/Kgm per Post Code Group as a Defined Zone.
I cannot work out any way that I can do this within the current Zone Table methods.
(In passing I notice that Ecwid - says that it can handle this OK although I have never tried it in action.)
Does anyone have suggestions, or knowledge of a plugin used for Australia or modifyable to our use.
Obviously a satisfactory method would find wide usage for others in Aus.

[frank18]

You may want to take a look at the Ozpost module:

https://www.zen-cart.com/downloads.php?do=file&id=899

RodG has a done a fine job with this module and as far as I know it caters for a variety of carriers in Australia. It runs on a free trial basis and then is based on subscription.

Cheers / Frank

[Big Ben]

Thanks Frank,
Particularly for the quick answer.
I had a good look at this before I added this post and I know Rod operates from here and has done a good job with it.
It really does not fill our needs - which is also why I tried to spell out our freight profile in such detail.
I was looking to set our own rates independently - using LESS Destination zone groups than those set by our biggest freight company - absorbing some of the variances - Would you believe in an attempt to Simplify the big number of rates and conditions and frequent changes they set, at the same time allowing us to use other specialist carriers for some of the more remote rural and outback areas.
Thanks again / Ben