[Koha] (no subject)

Hi, We are a small special library (archaeology and cultural heritage) of about 80.000 items. We're currently considering changing our library system and are considering Koha. In order to get all our data in the system, we would require the use of the 773 and 774 fields. I've been experimenting a bit with koha 3 (zebra enabled), but I can't seem to get these fields to work. I'm trying to create links between records using the 773$w and 774$W subfields (control numbers). I've tried to find out as much as I could from the perl scripts, but I'm not very familiar with the language. Does Koha do anything with these fields? If so, what does it do with them and how should I use them? Kind regards, Maarten