iOS Duplicate push notification issue

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I have an interesting use case, which poses some problems I am not sure how to solve.  I imagine this has to have been a problem for someone in the past, but I cannot find any info on it.

Here goes...

I have an iOS app which has federated users at my company.  There is a back end admin web site which controls content distributed to the users based on the AD group they are in.  An admin can assign one or many AD groups to a document.

I want to send push notifications to users when a document has been published to an AD group they are a member of, but I dont want to send them duplicate notifications.  I am registering tags in the iOS app as AD groups.  For example, say a user Jane is a member of the following:

[[UAirship push] addTag:@"AD_Group_A"];
[[UAirship push] addTag:@"AD_Group_B"];

Imagine the member assignment is as follows:

AD_Group_A:
John
Jane

AD_Group_B:
Jane
Jim

If a new document is created for groupA, John and Jane will get the notification:  "A new document named DocX is available"

All is fine up to this point, but now what if an admin adds AD_Group_B to DocX.  So now AD_Group_A and AD_Group_B are assigned to DocX.  The admin code will notice AD_Group_B is a new group and send a push notification to tag: AD_Group_B.  Now Jane and Jim will get notified.

The problem is that Jane was already notified before.

Is there a way to ID each notification and conditionally show a notification by running code to check whether the user already received it?  Or other solution?