Multiplex single SCB to multiple ports in application?

On a PSOC 4000s, 2 x SCBs are available. However I have a need for 3 x UART bi-directional interfaces. SCB1 is mappable to 2 different ports (P0, P3), SCB0 to a single port (P4).

Is it possible, during run-time in an application, to multiplex SCB1 between P0 and P3? I'm thinking build/synthesis only allows a fixed SCB-to-port mapping, but that would make a world of difference if this can be dynamic!

If not possible, I'm open to alternate approaches. UART is not a requirement, slow baud rade is okay (e.g. 9600) but flash memory is tight. SW UART component is Tx only. I feel writing my own Rx or protocol would be a time sink.

Thanks!