NPCs composing that spawngroup :

inferno_goblin_captain (100%)

NPCs spawning around that spawngroup :
(Max range : 100)

soldunga_fire_goblin90, range=38 (47,-665,44)

fire_goblin (50%)
fire_goblin (50%)

soldunga_223539, range=64 (39,-634,41)

soldunga_223540, range=67 (53,-622,40)

soldunga_223542, range=36 (47,-697,44)

soldunga_223544, range=13 (83,-696,44)