Group fighting is possible and effective with a large range of builds, but it is important for you to realise that the techniques of group fighting must vary based on the build you have.
Agility based characters must make use of their high athletics to string groups of opponents in to more easily managable 'chunks' of 3 or less. This way they can isolate individual players and prevent players from simultaneously holding. This means that yes, they need to kite. Characters using 101+ speed weapons with approximately 180 weapon proficiency will notice that they should be able to beat outranging swings with a sudden target change and left swing. Make sure you hit the head as your lower powerstrike means that you need to hit the head to be dangerous. Remember that extreme athletics builds will die in 1-2 hits depending on speed bonus and hit location, so you have to be careful.
Balanced Characters are generally on the order of 5-7 athletics and will not have a speed advantage on the group of opponents. This means that it is impossible to 'string them' in to smaller more easily managable chunks as the group will inevitably catch up on them. This is where group fighting becomes more complicated, but shouldn't be foreign to anyone experienced with group fighting in native. If you are versing groups which are synchronised through the use of voip, it will become difficult without a shield, as they will attempt almost simultaneous strikes and stun hitting.
The general idea of group based fighting with equivalent speed is you must actively suppress as many people as you can at once. This means that if you get 'focused' on an individual opponent you have lost. If you are versing an group of 3, you will find that you will be able to actively suppress atleast 2 of those players at once, you must move around to keep the third from in turn suppressing you.
The simple algorithm for this is: Block player 1 (or chamber if the opportunity presents itself), drag chamber to or attack player 2. To improve your group fighting further you must learn how to keep the number of players in striking range of you equal to or less than 2 and make sure you integrate attack cancelling to target changing. This is because if you judge that a player has beaten you to a swing, or you have a number of players greater than 2 in strike range without teamhits, you must be able to attack cancel, block and switch target again. The use of tilde tapping may be required.
Note that I have not gone in to the use of group fighting techniques when you're vastly outspeeded. I have not experimented with this, but I presume you must rely on forcing thuds/teamhits to get anywhere. Target changing will still be important.
Now an interesting group fighter I have is my 9ath shielder, (10-27), which can prevent simultaneous hits using a shield while maintaining deadly on the target change headshots. Due to the low shield skill (4), he changes to 1h no shield in 1v1 and is perfectly specced to hunt down groups of unmounted ranged.
If you intend to group fighting with a 24-15 polearmer I recommend limiting your reach to 120ish, or your opponents will abuse backswing stun/blocking/interupting. The longaxe is useful for this as it is long enough to keep opponents at a distance, damaging enough to kill in 1 hit and short enough to prevent backswing block.
