Humans have become the leader of the Virgo Cluster faction, 800 billion years in the future. Our enemy factions are, the Fornax, Centaurus, and the Coma clusters, as well as a few dozen lesser factions.
Recently, intergalactic astrophysicists and astronomers have discovered that all of our neighboring galaxies and clusters will disappear behind the cosmic light horizon in approximately 6.9 billion years.
Now, every faction is making a united, concerted effort to move every one of the 1 trillion galaxies within 10 billion light years of the factions into an sphere of radius 2.5 billion light years to prevent them from disappearing.
The astrophysicists have determined, due to physical and space-time limitations, the maximum speed that each galaxy can travel is $10c$, to prevent the galaxy from disintegrating. How can the factions accomplish this within a reasonable timescale, assuming that everyone is very interested in saving billions of galaxies from an unknown demise?