I couldn't find this in the rules, but that could be because I'm just... I don't know.
Anyway, I couldn't find anywhere in the rules that stated you COULDN'T chain off a single building multiple times.
For example, if I have a Workshop, can I build ANY amount of Archery Ranges and Laboratories for free?
While Chad is correct, to answer the other part of your question: Yes, you may chain off the same building multiple times, just don't duplicate. So the Workshop will allow a free build of one Archery Range AND one Laboratory.