In some cases it's useful to determine the applicable default group sequence depending on the state of the validated object. E.g. an attribute foo should only get validated if attribute bar has the value "qax".
Hibernate Validator has a mechanism for this in form of the group sequence provider SPI.
Mailing list reference: http://lists.jboss.org/pipermail/beanvalidation-dev/2013-June/000900.html