Long Distance Relationship

Two friends are currently faced with a long distance relationship. Is there a specific prayer or blessing that would be appropriate for this situation (those separated from loved ones)?

I do not know of a specific prayer just for such a situation. I think that they should take any one of the chapters of Psalms that touches them and arrange to say it together at the same time and to let the astonishingly poignant words sail upwards to the heavens.