cumulative upkeep ?

[joshisme]

i put 2x phyrexian soulgorgers into play on the same turn. The next upkeep, can i sacrifice one of them to keep it in play or am i forced to sac them both to pay their cumulative upkeep cost?

[Nihil Credo]

You can.

[Opterown]

You can keep one.
Next turn, though...