Bjorn, SM7IUN has brought my attention to a potentially important caveat in editing the start.sh file to activate two entirely separate receivers on an RP-16.
The RP-16 is a Linux device, so the start.sh file must be compatible with Linux. However, if you edit a Linux file using Windows Notepad, the edited file will come out with <CR><LF> at the end of each line, rather than the Linux standard <LF>. This, in turn, could result in its no longer working under Linux. While I have not yet had this problem with my RP-16s, it's worth knowing about.
Fortunately, there is an easy solution - Notepad++. Written by Don Ho, it is freeware, and senses whether a file selected for editing follows the Linux convention or the Windows and ends lines appropriately. A worthwhile precaution, I'd say.