Cisco Router

I have 2 Cisco ata186 with 2 voice ports at 2 different locations with static real ips. I make calls direct ip to ip without using H323 proxy or Sip proxy by using nn**xxx*xxx*xxx*xxx# and it works perfect. Now I have a 3d location with 8 static real Ips and a Cisco 827-v4 Router. can anyone help with the configuration of the 827-v4 4 voice ports so that I could place calls from them to the numbers on the ATA186 units witout having to go throug a proxy or a voice provider?

Thanks