Andrzej,
When PilotAware is first booted, it generates a random Hex I.D. Code, shown in the first box on the Configure Screen. This is so that the unit will transmit a unique PilotAware identifier.
When installed into an aircraft, this must be changed to the unique ICAO Hex Address allocated to that aircraft by your national aviation authority. In the U.K. we get this code from the CAA's 'G-INFO' website, but as you are not in the U.K. you will need to check your aircraft paperwork or speak to your local Aviation Authority.
In order for your own PilotAware to filter Mode S or ADSB from your own transponder, this Hex Address MUST be changed so that both the PilotAware and Transponder have the same ICAO hex address installed and this MUST be the Hex code allocated to the aircraft by the National Aviation Authority. This is irrespective of what Mode CS Selection (if any) you are running.
The same principle also applies in order to 'combine' ADSB and PilotAware signals coming from another single aircraft. In order to prevent this aircraft showing as two separate signals - which seems to be what you are experiencing, BOTH devices in that aircraft MUST have the same unique Hex Code belonging to that aircraft installed.
I hope this is clear.
Regards
Peter