I just started trying something tonight with our 9 month old.
If someone leaves the group or comes back she pulls in their direction like a freight train, if I leave the group with her she carries on the same way or makes a whiney I'm worried for them type of bark.
So tonight when the family went for a walk, I walked ahead with her at heel at a nice pace and kept her attention forward when ever she tried to look back, at each corner we stopped and sat in a heel position while we watched them walk towards us.
1st corner as the family got closer I praised, and kept repeating stay and rubbed her between the ears and just before they got near us, I about turned and heeled away to the next corner. 2nd corner same deal, except she broke as my son ran up and she started pulling towards him, I corrected her and brought her back to a sitting heel, as the rest of the family got closer she broke again but I corrected her and when she was calm we moved on, 3rd corner we sat and waited and I let the family know to keep walking and not look at her, she tried to break but nothing to bad she wanted to watch them walk away while sitting in a heel and then we followed and she pulled like a train as normal, but I just corrected her and heeled and she settled down and then we picked up the pace and caught up, and sorry for a bit of gloating here but I'm very proud of her atm and how quickly she learnt to control herself, coz the 4th corner she actually sat and waited, didn't break, the mrs and I talked and she said hello to Belle and when I released her from the heel sit she went and said hello to the family, normally she would of been going crazy like she hadn't seen them in months.
I'm going to keep doing it each time more then one of us go on a walk, let her get more relaxed with me leading her away, waiting etc, and then let the wife or eldest lead her while they walk away from me, because after the last corner the wife took her and walked ahead as we got closer to home, Belle did go a bit stupid when they came walking back to us, but she said her pulling wasn't as full power as normal. I'm still chuffed at how quickly she did catch on and settle herself down though