Delivery Charges by Suburb – not only postcode

Hi,

I’m located in Sydney, Australia and run a food delivery website that services specific areas within the Sydney region.

At present I have 3 shipping zones setup which are incremental in price due to a number of factors – these are identified by postcode.

The problem I have is that in Sydney, one postcode could be shared by upto 15 suburbs and geographically the suburbs could span 25km+ / 15mi+ from eachother.

I need to be able to set my shipping zones by suburbs.

Would be great if there’s a plugin, otherwise open to custom coding – just don’t know where to start.

Thanks