Main Site and Remote Site

Main Site and Remote Site

We have DC with Patch deployment and OS deployment in main site. Now we have a remote site that we are setting new Windows machines. Main site and remote site are connected via LAN ( MPLS connection)
Currently all the machines in remote site have desktop central agent installed connecting to main site desktop central server. We want to do  the following
  1. Create a distribution server in the remote site for patches /OS deployment- pushing of images in remote site.
  2.  Want to use LAN connection for replication of data for patches / OS deployment images from main site to remote site.
  3. Since remote site windows machines already have agents installed that point to main site , how can we change the agents to talk to distribution server in remote site. 
  4. Is it possible for agents in remote site to communicate with distribution server in remote site and if the distribution server is down, then communicate with central server in main site. 
Any assitance will be helpful in this matter.