This would do it:
model.setCollideMask(BitMask32.bit(0))This sets a single bit (bit 0) on the into collide mask of all GeomNodes and CollisionNodes at model and below. Since your from object probably has at least bit 0 set on its from collide mask (the default is most bits on), this will enable collisions with all GeomNodes under model.
However, this is still a terrible idea. Collisions with visible geometry is about 100 times slower than collisions with actual collision geometry, even geometry of the exact same shape. This is because the collision geometry is optimized for the collision calculation, but the visible geometry is only optimized for rendering.
David