Mechanisms for data source computing system(s) to provide data to data targets. The data source(s) access an identification of common groups of blocks, each group being common amongst all or a subset of the data target(s). The common groups of blocks may have different scope such that one common group of blocks is to be provided to a different set of the data targets than another common group of blocks. Optionally, a selection mechanism may be used to assign priority in initiating multicasting of the identified common groups of blocks. The data source(s) then initiate multicasting of the common groups of blocks in the appropriate order to the appropriate data targets. Since the common groups of blocks are provided in a single multicast, rather than separately, the data is provided in a more efficient manner to the data targets.