Group 500 integration with RPD (RealPresence Desktop)

Hi,

1. We are using RPD (RealPresence Desktop). We have a DMA server by which RPD (RealPresence Desktop) are being processed for call. Now I need to integrete Group 500 Codec with RPD, So that I can make a call from RPD to group500 Codec and group500 Codec to RPD by dialing number. Is it possible? If possible, then need any license?

  2.  What  type of license does need for DMA server and what purpose are those used?

 3. If above solution is possible for same network. Then If I want to make call from different network then need polycom firewall?  

   Have need any license for firewall?

 4. Have need any RMX for these solution?

Also I would be very grateful if you provide me those solution and reference link or deployment guide/resource for my better knowing.