  Combined bounds on the Majorana neutrino mass for light and heavy neutrino
exchange mechanisms are derived from current neutrinoless double beta decay
(0{\nu}\b{eta}\b{eta}) search results for a variety of nuclear matrix element
(NME) models. The approach requires self-consistency of a given model to
predict NMEs across different isotopes. The derived bounds are notably stronger
than those from any single experiment and show less model-to-model variation,
highlighting the advantages of using multiple isotopes in such searches.
Projections indicate that the combination of near-term experiments should be
able to probe well into the inverted mass hierarchy region. A method to
visually represent 0{\nu}\b{eta}\b{eta} experimental results is also suggested
to more transparently compare across different isotopes and explicitly track
model dependencies.
