Duemilanove + 2 Popolu Ctrlers + Xbee + SoftSerial

I am using Pololu Micro Serial Servo Controller and a Pololu Low-Voltage Dual Serial Motor Controller with a Arduino Diecimilla board. I wish to add an Xbee Shield to the Arduino Duemilanove. At present I have the two controllers connected to TX (pin 1) on the Arduino Board. Once the Xbee shield is plugged in this is not available. Is it practical to put the Pololu Micro Serial Servo Controller on pins 4 & 5 and put the Pololu Low-Voltage Dual Serial Motor Controller on pins 6 & 7 and use the newsoftserial library thus leaving Xbee on pins 0 & 1? Or is this not the best solution. Please advise.