Unpossessable Nouns, Pragmatics, and Semantic Relations

Matt's reply to my proposal of a class of unpossessable nouns in
Boreanesian got me thinking! ...and thinking got me curious!

First of all, in the languages I speak, possessive constructions
indicate that there is some sort of relationship between two nouns.
The semantic relationship need not be that of 'true' possession.
Other kinds of semantic relations can be referred to - the exact
nature of this relationship being determined pragmatically.

However, how exactly is pragmatics involved in the possessive
constructions of languages with a class of unpossessable nouns? Are
possessive constructions simply not allowed with unpossessable nouns
in such languages? If so, how are semantic relations other than
'true' possession indicated? Or perhaps the restriction only applies
when the semantic relationship between the nouns in question refer
to 'true' possession. If so, would other kinds of semantic relations
still be indicated through possessive constructions?

Hoping I'm not asking too much,
-Kristian- 8-)