You can configure Forte to do specific things on scene change with different plugins.  Here is a short video on how do use Kontakt in a Forte rack where each scene can change to a preloaded sample set in Kontakt:  http://youtu.be/j4nLSJoB9ro

The sample general concept applies to many other VST samplers, and potentially to any VST plugin that takes a long time to load its setup data.

For or information about Scene Commands, see http://www.brainspawn.com/documents/forte3help/scene_commands.htm?zoom_highlightsub=sampler