You can get help, but only one Torch will drop. In addition, a character can only hold one Torch at a time. The last brother killed will also drop one Standard of Heroes per character in game. All these signify is that you beat Pandamonium Event, and you can hold as many as you'd like. Ignore the level requirement, because it does nothing.

The portals can only be opened in Harrogath, Hell mode. Enemies also begin spawning when you enter, and are considerably more difficult than most enemies, despite how similar they look.

If you want to solo Pandamonium, the only character that can do it is a Frenzy Barbarian with level 20 Berserk Synergy and the best possible gear, or, the more popular alternative, a Smiter with the best equipment that Diablo 2 can afford.