i need a solution for this

head office has an ip of 172.10.10.0/24
i have a vlan address of 10.20.31/24 which has and dhcp lease to branch offices as WAN (internet) address over wireless
other office has 172.10.0.0/24 as their lan network
now i want to route the branch 1 2 and 3 network to the head office network.
please leave your comments.