I've made my own mobs. They work pretty much like swarms (slight difference) but for small, medium or large creatures.
Formation [Keyword]:
A formation is considered a single monster even though it is composed of several Small, Medium or larger creatures. Most single formations are Huge but some can be larger.
A formation is immune to forced movement (pull, push, and slide) effects from melee and ranged attacks. Close or area attacks that impose forced movement affect the formation normally.
A formation can enter or move through an enemy’s space; this movement does not provoke opportunity attacks. An enemy can enter a space occupied by a formation, but the space occupied by the formation is considered difficult terrain, and doing so provokes an opportunity attack.
A formation can squeeze through any opening large enough to accommodate even one of its constituent creatures. For example, a formation of humans can squeeze through any opening
large enough for one of the humans to squeeze through. See the Player’s Handbook for squeezing rules.
Formation Template (Elite Soldier)
Prerequisite: Small, medium or large humanoids, or humanoids mounted on large creatures.
Defenses +2 AC
Saving Throws +2
Action Point 1
Hit Points +8 per level + Constitution score
Size becomes Huge
Formation Traits
The creature gains the Formation keyword and its associated properties.
Powers
Formation Attack
Aura 1; the formation makes a basic melee attack as a free action against each enemy that begins its turn in the aura.