Hi German,
some time ago (Moodle 1.4) I wrote the CustomLinker filter.
It's primary goal was the ability to develop your own expressions to link where you want (basically external links). Anyway, perhaps it could be a good start for you to build your own custom filter.
Not sure if it'll help, but...
Ciao
Resource types
Resource linking
Aquest fil de debat ha finalitzat, així que no admet respostes.