To emulate a "join" transition in SCXML, you can use a single "default transition" (a transition without a trigger) originating from the parallel state, and use a cond attribute with "In()" predicates for each parallel substate you wish you join. You can find the definition of a join transition in the following paper: http://citeseerx.ist.psu.ed…

scxml_join_example.xml

<scxml>
  <parallel id="P">
    <state id="A">
      <state id="A-start">
        <transition target="A-done" event="t"/>
      </state>
      <state id="A-done"/>
    </state>
    <state id="B">
      <state id="B-start">
        <transition target="B-done" event="t"/>
      </state>
      <state id="B-done"/>
    </state>
    <transition target="done" cond="In('A-done') &amp;&amp; In('B-done')"/>
  </parallel>
  <state id="done"/>
</scxml>