Magneto vs Magneto constructs

[Biadetic]

If both players are playing Magneto, are the metal constructs spawned shared or is each construct specific to the spawning Magneto?

Example, start of round 1, player 1 has priority, creates a Construct, gains 1 power from it. Player 2 the resolves their construct, would they then gain 2 power for 2 constructs being in play or do they only count their own? (which in turn would mean can there only ever be 2 constructs in play or 4 if both players have magneto). 

Thanks. 

[AMG_Pagani]

This is included in the FAQ that releases along side Magneto - Each Magneto's rules reference their own Constructs.