Our 7 month old GD won't let our 23 month GD play with anything!

[Liza, Halle and Finn]

We have two doods: Kachi, a male 55lb who is 23 months old, and Halle, a female 28lb who is 7 months old.  Our problem:  Our otherwise very alpha male lets his much smaller, baby sister take everything away from him. He goes to the toy box and grabs something out, and she immediately goes over and takes it from him.  Even if she has her own toy, she will take his away, and now she has two!!  He will very calmly just go over and get something else out, and she'll take it from him. He'll calmly retrieve the original item he had, and she'll steal it back...and on and on and on! The weird thing is that in every other instance, it is apparent that the puppy submits to her bigger brother (eating, sleeping, etc). Also, Kachi has never shown any aggression towards her.
This drives my husband and I crazy because we feel bad for our 'big' dog, but Kachi (our male doodle) doesn't seem to mind.  Or does he??
 I just don't know enough dog psychology to read into what this means!.  Anyone else have this situation? And, if so, did you do anything to teach the the younger dog that they need to share? Or do I just let Kachi deal with it?

[Lynda Kamrath]

We have a similar situation, but our dogs are both male and about the same size. They have absolutely loved each other since the day they met, but the younger dog (Groucho Too) is obviously the alpha dog. They play and wrestle all the time, but if Hondo gets tired, he just lays down. If Groucho Too tries humping him, he just sits down. They both are about 100 pounds, so wrestling in the house is out of the question. They eat in different areas (one inside, and one outside) but Groucho Too will frequently leave some food for Hondo. Hondo never leaves any food for Groucho. They each have their own beds (inside and outside) and their own positions in the cars. I think dogs will work out the order and rules if they are left to their own resources. Our only problem has been overexuberance on the part of Groucho Too. Hondo is such a totally mello doodle.