Luk 20:33 Therefore in the resurrection whose wife of them is she? for seven had her to wife.
Luk 20:34 And Jesus answering said unto them, The children of this world marry, and are given in marriage:
Luk 20:35 But they which shall be accounted worthy to obtain that world, and the resurrection from the dead, neither marry, nor are given in marriage:
Luk 20:36 Neither can they die any more: for they are equal unto the angels; and are the children of God, being the children of the resurrection.
Luk 20:37 Now that the dead are raised, even Moses showed at the bush, when he calleth the Lord the God of Abraham, and the God of Isaac, and the God of Jacob.
Luk 20:38 For he is not a God of the dead, but of the living: for all live unto him.
We know that angels are very powerful. 2 Kings 19 provides on example, in which an angel destroys 185,000 soldiers in one night. We can also from this see that they can at least move around pretty fast. St. Thomas Aquinas would say that they move at the speed of thought. As we see in Luke, the saints in heaven are like angels. Therefore, we can conclude that they would have no problem getting from one place to another if that were necessary for them to hear our prayers. I would say it is not. It was only mentioned for the purpose of a speculation converning the interaction of the saints on earth. However, the communion of the saints is generally limited to the idea of the saints hearing our prayers while in Heaven. Note that this is only one arguement. I am in the process of researching others.