This being the Gamemasters section of the forums I figured I would post what I am doing with the premade campaigns here.
As most of us already know Final Sanction and Oblivion's Edge are already linked with some really good writing, however I felt the need to make good use of the printed Extraction already in the book and tie it in with these other two missions.
How I am running this is actually quite simple, my players will begin going through Final Sanction starting this Friday and will complete it as normal. Continuing on from there I will do the first segment of Oblivion's Edge up until Hit and Run.
During the Hit and Run portion of the campaign instead of the captain suggesting weaking targets, he will feed the players a distress signal from an the start of extraction stating that a planet within the same system has just been overwhelmed by the advancing invasion, however an ordos xenos inquisitor has sent a distress signal and activated a beacon with information about the advancing hive fleet.
Now of course my players may opt out of attempting to fly into or near the swarm for this information, however if they decide to do so, run the extraction mission as normal, and simply add the objectives into the overall objectives of Oblivion's Edge, and return them to the Emperor's Wrath once the mission is over.
With the inquisitor now on board the players and NPC's may gain some significant insight into what the tyranid hive fleets numbers are like and how to identify key targets among their number, or something to that effect.