I was able to complete this by generating internal boundaries for Carrier Route data using Voronoi. the endpoints to query for carrier routes exist on [boundaries-io.com][1] 
here is a link to a blog where i figured it out...if this helps someone.

(I don't own this blog)
https://longair.net/blog/2017/07/10/approximate-postcode-boundaries


[![enter image description here][2]][2]


Final zipcode 60630 with carrier boundaries generated:

[![enter image description here][3]][3]

*disclaimer I work for boundaries-io.com*


  [1]: https://boundaries-io.com
  [2]: https://i.sstatic.net/962Mv.jpg
  [3]: https://i.sstatic.net/PiAgh.png