The way I've always made iced teas, including while at work is to make a tea using boiled water as you usually would and then to shake it in a boston with ice to cool.
If making a jug I would just make the tea in a jug using 2-3bags remember to let it steep for three minutes take the bags out add ice, and some nice lemon, make them rounds not wedges, the rounds look nicer and feel more summery then wedges.