The list files that Pi-hole uses are defined in below config file:
pi@noads:~ $ cat /etc/dnsmasq.d/01-pihole.conf
[..]
addn-hosts=/etc/pihole/gravity.list
addn-hosts=/etc/pihole/black.list
addn-hosts=/etc/pihole/local.list
[..]
You could create your own new config file like for example:
/etc/dnsmasq.d/99-my-settings.conf
Containing:
addn-hosts=/etc/pihole/lan.list
And restart to apply:
sudo service pihole-FTL restart