If you are using a windows VPS (Amazon in my case) you just specify different ports, but you still run the masternode on 8886. This is what my second Masternode config looks like

rpcuser=USERNAME
rpcpassword=PASSWORD
maxconnections=256
rpcport=8887
port=8887
masternode=1
masternodeprivkey=PRIVGENKEY
masternodeaddr=YOUR_IP:8886   



The important part being that you DO NOT CHANGE the port on the masternodeaddr you leave it as 8886.

You are running this from a second datadir of course, but masternode start command works just fine without port issues, and has been on my AWS for the last couple of weeks. I have never used a hot-cold wallet so I dont know anything in that respect, but this is how I run two MN's on one Windows server. Hope I am not being extremely redundant, Just trying to help out.