Perhaps its semantics but one WeeWX instance can only run one driver. The common way around this limitation is to run the second 'driver' as a service and augment packets/records as applicable. This requires one of the drivers to have been written to run as a service - not that difficult, most of the underlying code remains the same it is just really the interface to WeeWX that is different. Of course this ignores any issues associated with multiple SDR hardware devices.
And of course the other approach is to run two instances of WeeWX, not that difficult.
Gary