Realport on TS8 how the Ports are assigned

We have a TS8 with 8 Ports and 6 POT Lines.
If i install the Realport Software on Windows 2012R2 only 5 Lines are detected.
The Communication over Port 771 works and a can call to outside from the determined Modems.
How the assignment is done by Realport to the specific Lines?
How i can define which Line should be used for the specific Server or Com Port?
What i want is:
4 Lines on Windows 2012R2 System A
1 Line on Windows 2003 System B
1 Line on Windows 2003 System C

So i want to adjust the used Lines for Example to define that the Line1 working on Windows 2012R2 “System A” are assigned to the COM Port on Windows 2003 “System B”.
We have used Serial/IP from Tactical Software is which creates virtual COM Ports and uses TCP Sockets on Digi TS8 but then the COM Ports are not shown in Windows System Devices.
Is there another Solution from Digi for Windows available to configure virtual com ports.

The way I would try to achieve this is to first install all 8 ports on the first system through the RealPort wizard (when you install the RealPort driver). Then afterwards, drill down the the RealPort properties and unselect the last 4 ports, leaving only the first 4 selected/checked. By drill down in the properties, I mean double-click that device in the MultiPortSerial Adapters category to get into the RealPort properties. I forget where exactly, but if you dig a bit, you should find an area where you can select what ports to actually use.

Then repeat this process on the other 2 systems, except only check the single ports you want each of them to use. For example, if you selected ports 1-4 on the first system, then select only port 5 on the 2003 B system, and only port 6 on the 2003 C system.

Does this make sense?