Devoting RX and TX lines in Comm. System

So, I am currently working on a project in which both an XBee Pro and and micro SD card are attached to my Arduino. I am attempting to record data on the SD card as well as intermittently send live data via the XBee module. I have heard this will cause a problem in regards to the of the RX and TX lines since they can only be used by one device at a time. Is there a way I can control which device is receiving the data? Thanks!

Is your micro SD really a Serial device - meaning controlled by hardware or software Serial class?