I agree with GK that you're much, much better off working entirely in Carrara and cutting Poser out of your workflow entirely.
I know it's awkward at first, but trust me; it won't take long before you're wondering how you ever did any other way!
Here's a few tricks for larger, more complex scenes:
Set up your figures one at a time in a separate file; once everything is posed and textured to your liking, simply save the figure to your content browser. Once you start work on your main scene, simply drag and drop the figures wherever you want 'em to go. (The replicating will still work)
One of the most common mistakes/misconceptions I see from people migrating away from Poser is the urge to put way too much stuff in a single scene all at once. You're always, always better off rendering your scene in layers. (Not to be confused with passes)
Carrara gives you all the tools to do this such as shadow catchers and premultiplied alpha options in your image format. It's really easy to break big scene into smaller pieces and composite them together in an image editor with Carrara.
You don't want to end up with a scene that takes days to render as well as running through all of your system's memory.
In the end everybody here wants to see more people using Carrara, so stick with it and don't be afraid to ask as many questions as you need to!
Good luck!