Comment 26 for bug 894943

Note to whoever develops this:
Prism Forwarding allows modder to specify Prism sharing on a per-BuildingType basis. There are relevant checks in PrismForwarding.cpp and Hooks.Prism.cpp - search for PrismForwarding.ToAllies

Modder should specify individual prism towers as allowing shared beams as well as this option having to be on (iff the option is included).