Among the three broad classes of Identity-Based Encryption schemes built from pairings, the exponent inversion paradigm tends to be the most efficient, but also the least extensible: currently there are no hierarchical or other known extension of IBE based on those schemes. In this work, we show that such extensions can be realized from IBE that conform to a certain abstraction of the exponent inversion paradigm. Our method requires no random oracles, and is simple and efficient.