Dual VPN Routers?

I have a bit of a situation. First the setup. I am part of a 3 part stores. We have a system that is mostly managed by the software supplier. I say mostly because the vender allows me to take care of many of the small support issues due to my basic knowledge, to the point that they have given me admin access to the server. Store 2 has the main equipment, server, static ip, generator exc. Store 1 and 3 connect to store 2 through VPN. There are a lot of other aspects with our server connecting to our main warehouse and so on so out inventory can be check by online shopper's. The problem. Our sales staff used to be able to connect to our store server when on the road using RDP. We had some attempted hacks bring our system to halt, so they disabled the RDP options for now. They are having a hard time finding newer secure routers to replace the ones we have that will work with everything. My sales staff is having a lot of problems not being able to connect. I have a spare static ip on the WAN I'm not using. Can I connect a second firewall to the network using to manage VPN's for my sales staff? That would eliminate the need to change the entire setup at all 3 locations. The router that is there currently is static. Any DHCP's that are handed out, are sent from the server. I just can't find much information about one LAN being connected to the WAN with 2 separate units, and not sure if this is possible. All the information I have found seam to relate to having to connections for splitting the bandwidth. In this situation I just want to have a way for my sales staff to connect. Thank you in advance for any help. I am also not very experienced with reddit yet, so if I am doing anything wrong with this post, please let me know so I can correct myself. Thanks, Partsjunky