Ok (grins evilly, loving a nice bit of utter chaos)
Lidda (who I'm going to have to look up, because I don't have the book she's in ... or I'll have to make her, at 12th level ... ick!) is going to, out of the kindness of her heart, call down softly:
Hey. Both of you. There's a dire bear about to attack you. It's over in those pine trees to the right.
Unfortunately ... neither Claire nor Narrin have a reasonable reaction to this. I don't know why. Perhaps it's the sun. Perhaps it's the fact they've been threatening each other, and are both scared.

Perhaps it's because both are inexperienced. Perhaps it's because ... well, it could be anything.
Claire whirls to face Lidda's position (and mistaking Lidda for someone else) : You're the one with that party who injured my friends. Now I will kill you!
And the same time, ignoring what Claire said altogether:
Narrin: I KNEW it was a trap. You set me up! A trap, a trap! Well, you filthy treasure hunters, now you die!
Lidda, for just a moment, is in shock, her mouth hanging open. She recovers an instant later, but she no longer has Surprise (although her two self-declared foes are still flat-footed)
Aroused and angered by all the yelling, the dire bear (I'll have to wing that one too) roars a challenge, which shakes the woodlands. On it's turn, it will charge.
The half-orc ranger (5th level, specialized in two-weapon fighting, a Drizzt wannabe, and an ally of one Forrester

) who was trailing the bear, and who is an ally and friend of Narrin, hears Claire and Narrin shout, the bear's roar, but does not hear Lidda.
When he sees the dire bear charge, he will charge, on his turn. His friend Narrin is in danger from an unknown foe, and from the dire bear.
Claire and Narrin both do Spot checks for Lidda, as Lidda called down to them. Both, by some fluke, roll natural 20s, which is an automatic success. They see her, see precisely where she is, see the crossbow she has aimed at them (which both interpret as an assassination attempt. They do not know Lidda is not a killer by heart. They think, in their sudden adrenal surge, that an Artemis Entreri is upon them. So they REALLY freak out now.)
Both intend to attack Lidda, on their turn.
At the top of the far hillock, Hennet the Sorcerer overhears the uproar down below, and with a bellow this hot-headed sorcerer (11th level) charges downslope to help Lidda. But he is 500 feet away from the combat.
The others at the top of the hill also charge, charging right into a nest of Damaran vipers (deadly poisonous, death in minutes.) The vipers gain surprise, and successfully bite Mialee and Tordek. Tordek starts killing them, after making his save, but Mialee is in real trouble, having rolled a 1 on her save. Jozan the cleric breaks off the charge to help them both.
Jozan shouts to Hennet for help, but Hennet decides to go and save Lidda, who is obviously in real trouble. Hennet shouts back that little Lidda is going to die if he doesn't save her, she's an old and dear friend, and he has to help her.
(Thus, Mialee, Tordek, and Jozan are out of the fight.)
Claire, Narrin, Narrin's friend the ranger, the bear, and of course Lidda herself hear the shouting 500 feet away at the top of the hillock. Lidda realizes her friends are in trouble. Claire realizes all her enemies have arrived. Narrin realizes it was a big trap, a huge setup by this elven female and her friends. Narrin's ranger friend doesn't know who it is, concentrating on protecting Narrin. The bear doesn't care. The closest person is the tastiest meal, in it's opinion.
Initiative is rolled.
Lidda rolls a 27.
The dire bear rolls a 23.
Hennett rolls a 20.
Narrin's half-orc ranger ally rolls an 18.
Claire rolls a 15.
Narrin rolls a 9.
Then all bedlam breaks out.
(If anyone has a 5th level ranger to supply, I could use him or her!

)
(I don't have the Monster Manual 3.5. Will just have to wing the dire bear.)
(I am assuming Hennett is 11th level, for the purposes of this combat.)
If anyone wants to contemplate how this mess would turn out, feel free to describe your thoughts!
If it's too much of a mess, don't bother. It's only hypothetical, in any case.
(The point of this combat is to understand the capacity of rangers and sorcerers, character classes I have never played, or really understood. And, to see what Lidda can do, and would do, in this fiasco.)