You mean the flaming salamanders when you enter from the 4-way snow canyon?
Buff up before you go in - prot evil circle, haste, defensive harmony, maybe recitation and prayer (they stack) - better if cast inside cause they debuff you enemies, but takes a while - plus a couple of free movements, protection from fire, and draw upon holy might, strength, etc... Also key buffing spells for melee combat are courage and hope.
Have the bard singing the song of sith for the armor bonus and regeneration.
Then enter and immediately cast 2 of each simultaneously - web and entangle - 4 total. I have 2 sources for each (F/D, R/C, F/C, and Bard). And then beat off the couple that make it through with your frontliners while summoning some undead meat shields between your party and the rest that are stuck. Fire and water elementals work well against the fire salamnders, too, but can take damage from your cold spells.
And go from there using missile weapons and damage spells once the couple that make it through are vanquished.
The web / entangle approach is a bit easier if you pickpocketed the rings of free movement, and I found one in a treasure location, too. Otherwise, just prebuff with the free movement spell, so your frontliners don't get stuck, accidentally.
Also, throwing greater mailison, a curse, recitation, or prayer, after the first trap spell helps to keep the far enemies stuck.
I've found "entrance traps" like these, many times are the hardest part of a level. Once past this, you can lure enemies one at time (works best with scout who can hide in shadows), if they don't use call to arms. If they do then web and entangle them at chokepoints, with undead as meat shields, and cast damage spells on them to create a "killzone" while they are stuck, or pick them off with ranged weapons.
Renew meat shields by re-summoning when they die off. Undead friendly killzone spells are any cold-based spells (especially useful against fire salamanders). Cone of cold and ice storm and otukes freezing sphere come to mind.
Hope this helps....
EDIT: after the initial entrance, you will come upon friendlies you probably don't want to hurt in collatoral damage so use of area of effect spells to do damage is not advised. Just lots of summons and targeted damage and holding spells (when needed) and ranged attacks.
EDIT 2; After the inital volley of trapping spells, slow and grease spells are good, too, if it looks bad. Actually, a grease spell can sometimes stop frontline enemies in time with a simultaneous trap spell, or right before it.