I don't know if this has been discovered before, but in a blood scenario, after the unit is produced, instead of tasking the units to an area, you can task it to a relic cart, and the unit will move to the relic cart no matter where it is. A looping change ownership trigger should also be put on the relic cart, to prevent it from being converted.
Also, an option for people to cancel the gathering point should also be created, because if the relic cart is away from your base and some enemy units come, you wouldn't want all newly created units to run away. This can be done, by having a king on a separate two tile island. If the king is on one tile, the gathering point is activated, but if the king is on the other tile, the gathering point is deactivated.
Just an idea for people making multiplayer blood scenarios, a gathering point would be very convienent and save a lot of time for players.
Condition: Object in Area (King on one tile)
Effect: Task object from spawning area to relic cart
This trigger is so that having the king on one tile, the gathering point is activated.
Condition: Object in Area (King on other tile)
Effect: Task objet from spawning area to a location a few feet away from there
This deactivates the gathering point, and units will stay right in your base.
Effect: Change ownership of relic cart to player ?
This prevents the relic cart from being converted.