Geekfam submitted a new map: Invasion G - I've recreated invasion in Halo 5 Read more about this map...
It might be possible to have an interactive switch in the red base behind a blue team one way shield. Blue would have to go into a base, activate the switch and that would have glass doors slide open for a locked room that would contain all three of the strongholds together. That would allow them to score and win. To allow red team to "win" a hatch on the top of the room could open to the stronghold room during the last minute and red team could score easily that way. In detail to make it balanced, the third stronghold could be semi separated so blue team can score on the two strongholds in the same location and the third would be slightly behind it, but separated. This would allow the last minute for the red team to gain only a few points, but the blue team could still clutch it and capture the two in the other room space. Place one way shields in the main dual stronghold entrances and exit's so red can't get in.