GSM and GPS with one serial port

Hello sir;
I have completed the project GPS and GSM individually .Now i want to use these both module with single serial port.I m using PIC18F4520 .
Like get sms from GSM module and send incoming GPS data to USER number through GSM module.
I do not want to use controller with 2 serial port.Please give me other idea.How it is possible in both hardware or software way .Please help me.

You can make use of Analog mux/demux IC like CD4052 an example diagram is available here:
http://www.8051projects.net/t48324/general-help-guidance-discussion/cd4052-multiplexer-issue.htm#post_48327

thanks i hv done this , it working very fine