PDA virtual serial port driver

I have an iPAQ PDA with Windows CE as OS.
I have my own application that listen to the unique PDA serial port
of the iPAQ witch receives, from an external device,
the NMEA data with some other data.
I have also Destinator with its SDK for the navigation purpose and
it requires an available serial port too.
This means I have two applications that needs one serial port each,
but iPAQ has only one serial port!
My idea is to apply a filter to the serial incoming data in order to send
only the NMEA data to the Destinator sw and the remaining data
to my application sw.
So I think that the best solution is to develop a virtual serial driver
for the unique serial port, that shares the unique serial port among the
two applications and witch filters the data for Destinator too.

Thanks in advance for any advice about it.
Regards

Giuseppe Maio