You can add additional RS232 serial ports to your computer. Then you can also run multiple instances of Butel's software, each within it's own window. To access, and control that computer from another computer in your home, over a network, use free software such as VNC. This would solve everything but the transfer of audio. Just get a multi-conductor audio cable to transfer the sound from all the scanners, and run it to your control room. This would probably be the most cost effective solution.
I was going to suggest streaming them over your network, but I think it would be too demanding on the computer resources, and bandwidth, for five scanners.
I have a feeling that the ScannerStation software may be too expensive for home use. I think it's intended market it news stations, and dispatch centers. But I could be wrong. Send Gommert Buysen and email requesting a quote.