Grouping?

Does anyone have either a link that clearly explains the "group" dynamics or perhaps could share some light on the group rules?

1) If you have 3 in your group of 4; why does it tell the group leader they must be a "leader" when they try to add a 4th (might be a while after the group initially formed)?  We have to all leave group and re-group.

2) Can you group with someone to help them with quests whether instanced or not?  Here's my grouping experience:

       a)  A friend just finished a quest in an area I just arrived in.  He wanted to group with me and hang out.  He started a group with me - then traveled to me (not sure if who travels makes the difference) and then was able to quest with me. It seems this didn't work other times we tried.

       b)  Earlier in the night, I grouped with a friend.  We later split up but then got on the "same" quest though we were on different steps.  I defeated Sadal in this instance and then turned to portal out and was totally surprised to see my friend had arrived.  Nothing would spawn for him so we left together; then re-entered the instance.  Same thing - nothing spawned.  We took the portal out and I turned in my quest.  Surprise Surprise!!!  My friend, although he didn't lift a finger in defeating Sadal got the quest finished, the reward/xp and the special achievement. (And he WASN'T happy) LOL  

3)  We tried to help a friend - grouped with him and could see him but when we got into the instance - poof . ..  he's Mr. White Carat.  I think we tried to travel to him but that travel feature was glitched.  (I also notice the wayshrines are getting very glitchy)

4) Are there some instances that can only be soloed?  So far haven't tried - other than the one attempt mentioned above.  It would really be useful if we could help each other with some of the tougher bosses.  The repair bills as astronomical and some of the less expert players or new ones could really use the help.

5) At what point does grouping with a higher level toon affect the XP of lower level toons?  Gradual?  It's hard to tell in this game.

At any rate; I am uncertain about the group mechanics and would appreciate any wisdoms my guildmates could share with me.  :)

1) If you have 3 in your group of 4; why does it tell the group leader they must be a "leader" when they try to add a 4th (might be a while after the group initially formed)?  We have to all leave group and re-group.

This is some bug in the game it is very annoying.

2) Can you group with someone to help them with quests whether instanced or not?  Here's my grouping experience:

       a)  A friend just finished a quest in an area I just arrived in.  He wanted to group with me and hang out.  He started a group with me - then traveled to me (not sure if who travels makes the difference) and then was able to quest with me. It seems this didn't work other times we tried.

       b)  Earlier in the night, I grouped with a friend.  We later split up but then got on the "same" quest though we were on different steps.  I defeated Sadal in this instance and then turned to portal out and was totally surprised to see my friend had arrived.  Nothing would spawn for him so we left together; then re-entered the instance.  Same thing - nothing spawned.  We took the portal out and I turned in my quest.  Surprise Surprise!!!  My friend, although he didn't lift a finger in defeating Sadal got the quest finished, the reward/xp and the special achievement. (And he WASN'T happy) LOL 

 a) Some quest's in the Game are SOLO only (I personally think this was a bad idea) it hinders people from grouping and helping out in dire times of a quest.

 b) Yeah that to is annoying it phase's people out of each other if there is a choice option for certain instances of the quest again it's a game mechanic. Best to pick same option with both people.

3) and 4) see above

5) I remember certain games was a 10 level difference before there was a 0 exp deduction for when the higher person killed a mob and lower exp deduction if the lower person killed the mob, I really haven't come into this situation yet in the game so I can not fully answer this without giving you my experiences. (short answer is) I am not sure what the level difference is before exp deductions.