1. A method for execution by a processing module in a distributed storage (DS) unit, the method comprising: receiving a request to store data from a requesting device; identifying first substantially similar data to the data that is stored within dispersed storage network (DSN) memory, wherein the first substantially similar data is stored as first plurality of sets of error coded (EC) data slices; comparing a number of other devices associated with the first substantially similar data to a threshold; when the number is less than the threshold: identifying, for the requesting device, first unique retrieval matrix of the first plurality of sets of EC data slices, wherein the requesting device can recover a decode threshold number of EC data slices within at least one set of the first plurality of sets of EC data slices based on the first unique retrieval matrix; transmitting, via a communication interface of the DS unit, the first unique retrieval matrix to the requesting device; and when the number is greater than or equal to the threshold: generating second plurality of sets of EC data slices to store second substantially similar data to the data; storing the second plurality of sets of EC data slices within the DSN memory; determining, for the requesting device, second unique retrieval matrix of the second plurality of sets of EC data slices, wherein the requesting device can recover a decode threshold number of EC data slices within at least one set of the second plurality of sets of EC data slices based on the second unique retrieval matrix; and transmitting, via the communication interface of the DS unit, the second unique retrieval matrix to the requesting device.