At 19th in Sol A I would fight young and cinder goblins. They'd be red,
but with a full group, and especially with an enchanter it would be
managable. I'm not sure if it would work without an enchanter at that level,
because you'd want to deal with one at a time. I'd also do it down next to
the zone to Sol B. That is from lavastorm entrance, down the windy stairs,
either through the hole in the wall or around by the pendulum axe, coming
out above the big doors turn right and straight down the hallway, which goes
down a ramp turning right to a small room at the bottom.
There's no spawn anywhere past the hall at the top of that ramp, and the
zone to Sol B is right next to it. If you get more than you can manage zone
out. You can try and root one on your way out and if you're lucky and come
back right away you may be able to catch that single one either still rooted
or behind the crowd going back. That shouldn't be the case all the time, but
it helps reduce the down time if there is a bad pull.
With an enchanter to mesmerize extras, and a group that will /assist the
tank you should be okay. If you don't have an enchanter you can try and
break the spawn with your lull/soothe/calm/pacify line. If you have a shaman
in the group get him to buff your charisma before using lull. The shaman can
also do some of the enchanter stuff by using malise to reduce magic
resistance for your casters, and speeding your tank and slowing the mob.
These things help effectively reduce the mob to your level. Of course the
shaman can't mesmerize though.