You would need to tell us what speed the internet connection is to the office, and how many wireless users if any. Your decision for which router you need depends on how many packets per second you need to process and how many firewall and QOS rules you want to add. Then you look at any other featur...

Any ideas as to what the Load Balancing Group will do?

The only solution I've found for this at this point is to compare the MAC addresses of each device to those listed in IP->Neighbors and rename them (or comment, but that doesn't seem to be working) to match what you have for their Identity.