Which process editor are you using?
One solution for this particular situation (having only 2 outgoing sequence flows) you could use a default sequence flow. So, in one of the sequence flows you write your logic and you configure the other one as a default sequence flow.
Unfortunately this is not yet supported in the Web Process Editor: https://issues.jboss.org/browse/JBPM-3704
AFAIK, jBPM5 eclipse plugin should support this feature.