I hope this answers your question: we support a * character at almost every
level of potential repetition in an HL7 schema. It means what is the
repetition count at that location.
For the example you give, it would be:
If HL7.{MSH:13} < HL7.{ORCgrp(*)}
We recently noticed that this feature is not well documented and we are
planning to improve that.
Hope this helps,
Ted
PS. Also note that HL7.{*} will give you the total segment count, HL7.{1:*}
will give you the number of fields in MSH, and HL7.{3:3(*)} will give you
the number of array elements in PID:3 if segment 3 is a PID. In other words
the * syntax works on index property paths that are not schema-based as well
as schema-based property paths.