Following my suggestion,
go to the EDIFACT segment that you use for creation of the E1EDP01 in the IDoc (my guess it is G_SSG5 (LIN).
use the UNB value as the first parameter to the useOnAsMany() (in the node functions methods) then use the G_SSG5 as the second and third inputs...from there add your existing rule.
In this way the rule will be checked for each line using the UNB single value.