J.
It is very possible. THE best breastfeeding source I've seen is www.kellymom.com. Also, I suggest contacting your local La Leche League...I am a member in Plano and a mom in my group is still nursing her 2 yr old twins successfully! Please don't give up, you can do it...oh, and you nurse whenever the baby wants. No schedules or you can diminish their food supply...the more they nurse, the more milk you make...also, if you're going to be working, pumping will help you keep your supply up when you're at work...simply pump whenever your twins would normally feed or would want to feed when you're home on weekends..this way you keep your supply up and build your bottle for the next day!
GOOD LUCK!