2. The method of claim 1 , wherein the determining hierarchical relationships further comprises generating a classification tree for a subject, the classification tree specifying subset relationships among the set of subscription queries via hierarchical levels and nodes; wherein each node in a left branch of a parent node at a specified level in the classification tree is a subset of the parent node; and wherein further, subscription queries that are not classified as either of a subset and a superset of the parent node are placed in an empty leaf node by traversing the classification tree for a first available empty leaf node.
2. The method of claim 1 , wherein the determining hierarchical relationships further comprises generating a classification tree for a subject, the classification tree specifying subset relationships among the set of subscription queries via hierarchical levels and nodes; wherein each node in a left branch of a parent node at a specified level in the classification tree is a subset of the parent node; and wherein further, subscription queries that are not classified as either of a subset and a superset of the parent node are placed in an empty leaf node by traversing the classification tree for a first available empty leaf node. 4. The method of claim 2 , wherein each of the nodes in the classification tree is associated with at least one of the subscription client systems based upon respective subscription queries.