How do I make enemies work together in packs and communicate with each other?

In other words, having enemy soldiers be extremely tactical such as when they kill you it'll play a sound like "Freeman is dead!" (I'm making a Half Life game, right now.) I think I know how to do it, but I don't the scripting skills to do so. Like where when a Combine Soldier says (with a sound, of course) "Go sharp, go sharp!" he darts around, and hides behind cover. I think you'd need pathfinding for this, and I don't mean to sound like requesting. I just need help, and I don't know the scripting skills to do this. Also, so the AI or NPCs have teams. Such as "Combine" or "Citizens." And how would I remove the leader board as well?

Also, possibly crouching behind cover would be nice as well, too.

Making the NPCs so complicated won't be possible. But making things work in packs might work, but the whole group will have to be grouped and use only one script. And all of the Sounds I can't help with sorry, you will have to use some robux to get some of this done.