SoftwareSerial .listen and SIM900

Greetings, I'm using an arduino Uno with these two modules: GSM GPS. The gsm modul uses sim900.h and inetGSM.h . I want to send gps coordinates to my server. Both of them works alone. Now i'm trying to use them together. Both libraries use software serial. I have to use gsm.listen() gps.listen() so i can switch between modules since software serial doesnt work in the same time. But in sim900.h doesnt have .listen command. The gps library have the definition of the ports outside the library so i could use GPS.listen() without any problems. But when i try to listen to the GSM module by using gsm.listen() i get this error ("'class SIMCOM900' has no member named 'listen' ) and i understand why i'm getting this error, but i don't know how to get the MC to listen to the GSM module. Any ideas? Kind thanks, Mate

Now i'm trying to use them together.

That is not going to happen. You are expecting both devices to be able to communicate with the Arduino at the same time. That is just not possible, as every one of the thousands of posts where that is tried have failed.

i don't know how to get the MC to listen to the GSM module.

You could add a listen() method to the SIMCOM900 instance, but it would not help.

Any ideas?

Get a Mega.