Navigate through multiple models

Hello,

I use attrs for my models.
A have multiple B. B have multiple C.
I use a grid to list C records, and need to show A names in the grid.
using the “C.b.a” path didn’t help.
I’ve used custom fields but didn’t know how to.
In addition I am not sure if I need to define a many to one relationship between A and C.

Regards.