IE can do this trick as well. It isnt jsut Firefox that can. Even Opera can do it. Sorry Firefox isnt superior cause it can open more than 1 tab upon startup.
IT is the same for IE as well. HAve the Tabs Open then go>Tools>Intener Options>Use Current and boom. 2 Tbas open upon start.
In Opera it is Tools>Preferences>Start with home page>Use Current.