I suspect that an application, such as Vue, that can use 64-bit addressing probably is the only fully robust answer to the question of how to add numerous figures to a 3D scene.   They do also require the hardware capable of making the most of 64-bit addressing, though, so that's not necessarily a short-term solution for most of us.  

I run Vue on a machine with the basic XP and 2Gb of memory.   Within those limits, where multiple figures are concerned, Vue is just as limited as Poser is, although there is plenty that it can do very well.  

Since I would like to make more of Vue's capabilities, I keep an eye open for a PC with the right combination of operating system and hardware and I am surprised by the number of PCs on the market which advertise a 64-bit-compatible operating system on a machine with a maximum 2Gb of memory (and no room for expansion).