Bukkit

Factions integration is already supported in LevelRestrictions and is very easy to configure.

To make a rule applicable to one or more factions, simply add your factions to a list:

factions: [FactionName, AnotherFaction, YetAnotherFaction]

For example... here we restrict Iron Swords and Iron Armor from the "Red" Faction:

rules:
    ironWeapons:
        description: iron sword/armor
        minLevel: 4
        factions: [Red]
        minMessage: You cannot use %m until level %min
        actions:
            - use
            - pickup
            - craft
        items:
            - 267
            - 306
            - 307
            - 308
            - 309

The above addition to that rule will prevent members of the Red faction from using/crafting or picking up Iron Swords or Armor until they are level 4. That rule will only ever apply to members of the Red faction. Others will skip it.