You need to check "Collision detection" for each actor, in the actor properties tab, before the hair will collide with anything.  A bit more awkward than setting up collisions for cloth, not an obvious step to take, but once taken collsions seem to work nicely.

(This one had me stumped, too, until only recently.  :lol:)

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Cage can be an opinionated jerk who posts without thinking.  He apologizes for this.  He's honestly not trying to be a turkeyhead.

Cage had some freebies, compatible with Poser 11 and below.  His Python scripts were saved at archive.org, along with the rest of the Morphography site, where they were hosted.