The problem:
In TOR, a character, regardless of his skills as a warrior, can only attack one enemy once per round (with some few exceptions from virtues and weapon qualities). This means that even Elven warrior Glorfindel, facing a group of 5 Goblins would be attacked 4 times after taking down one of them.
The solution:
Rather than changing the rules and letting characters have the ability to attack more than once (making Rewards like Spear of the Last Alliance basically worthless), we create a new type of enemey. These are enemies that is a group of foes that attack, and can be attacked as if they were a single enemy. This can then be described as if the character attacking is fighting several enemies at once, hitting more of them, even though in the rules, he is rolling for attack once.
The rules:
An enemy can be made have the new Group special ability. This comes in three "tiers" Gang (3-10 individuals), Band (11-20 individuals) and Horde (21-30 individuals). A Gang multiplies the Endurance by 3 and adds 3 Hate. A Band multiplies Endurance by 6 and adds 6 Hate and a Horde multiplies Endurance by 9 and adds 9 Hate.
In addition, enemies with the Group special ability can ignore 1 Wound per Hate spent, and add one Success dice on attacks per Hate spent.
Hate spent to ignore Wounds represent individuals of the Group falling, but the group still fights on. Hate spent to increase success dice on attacks represent the fact that more than one enemy attacks the character.
This is, of course, and abstraction to handle larger groups of enemies. As a LM, I'm more of the "cinematic" type, but this might not be equally suitable for other groups.

-E.