Can one dragon's destruction bring back all of my Keepers of the Shrine?
CDClarke is correct in his answer; you cannot do that what you propose.

To enhance on the reason why it is once again important to note that specific part:


  You can only use this effect of "Keeper of the Shrine" once per turn.


One thing that this specifies is that only this effect has restrictions; you can use the "This card can be treated as 2 Tributes for..." part as many times as you want/can. 

Another relevant thing to notice is that this quote references to the card in general. This means that the restriction applies to any Keeper of the Shrine you have. 

You could do what you propose if the card text said instead "You can only use this effect of this card once per turn." Card texts that you see contain such phrasing or similar refer to that specific copy of your card, restricting it from being repeatedly used (however it does not restrict other copies).

It is important to note those two different situations to effectively tell apart from a restriction that applies to a copy from that that applies to the card in general.