ConcurrenceExpression is the first choice for this pattern.

    <concurrence>
        <participant ref="first-activity" />
        <participant ref="first-activity" />
        <participant ref="first-activity" />
    </concurrence>

Another expression may be used :

    <concurrent-iterator
        on-value="alpha review, beta review, gamma review"
        to-field="__subject__"
    >
        <participant ref="alice" />
    </concurrent-iterator>

The OpenWFE implementation of the flow as found at http://is.tm.tue.nl/research/patterns/download/swf/pat_13.swf :

<?xml version="1.0" encoding="UTF-8"?> 

<process-definition name="pattern13" revision="1.5.1pre2" >

    <!-- body -->

    <sequence>

        <participant ref="a" />
        <participant ref="b" />

        <concurrent-iterator
            on-value="1, 2, 3"
            to-field="index"
        >
            <participant ref="x" />
        </concurrent-iterator>

        <participant ref="c" />

    </sequence>

</process-definition>