Overriding chroot path for ansible_connection=chroot

I cannot find any documentation for the chroot connection and I have tried asking on ansible and googling. When I need to override the ssh host, I can do:

ansible_ssh_host: '{{ ip | default("vpn.%s.%s" % (inventory_hostname, domain)) }}'

How would I do the same to override the chroot_path? - I need to keep the inventory_hostname.