The SCBs are hardwired to specific pins. So if you assign one set of pins(belonging to SCB0 in Cydwr) to your 1st SCB, you cannot connect any other set of pins belonging to SCB0 in Cydwr, to any other newly placed SCBs.
In other words, for the second SCB, you need to select a set of pins which don't come under SCB0 in CYdwr.
Is it possible, via register writes, to reroute SCB blocks ?
Register TRM seems to look like its possible.
I think it is possible to reroute by modifying registers. Not easy and must be careful.
I have the feeling that the fitter process for PSoC4 is not yet totally exhausted and that there might be made some improvements with upcoming releases of Creator (cross my fingers). We had a discussion here about the ref-voltage for the ADC which seemingly could be done better, now the routing of the SBC-IO-pins...
@MCU3, consider posting a tech case at -
"Create a Case"
and ask them if additional routing will be available in PSOC Creator 3.0, to be released soon.
Point them to this thread.