First let mention, that we strongly recommend you to use just one License Server service per network. A recommendable options would be to add your licenses to existing license server service or separate your networks.
There is a possible workaround by modifying system registry key (the "port" value) listed below to override the port and then manually configure all the clients.
HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Itoo Software\License Server
If you decide to modify it, please remember you have to configure all clients by setting the network license to the IP of the server instead of finding it automatically. This can be done using the "Change License Mode" wizard after setting Network license mode in the Configure the Network License window. Hope that helps.