Targeted scripts are not properly supported on non-unique RefIDs

See forum post https://forum.openmw.org/viewtopic.php?f=6&t=2262&p=30495#p30447

(RM-2311 from redmine: created on 2015-01-26 by scrawl ., , relates #2316, relates #2798 (closed), duplicates #4417 (closed))