Well it'll slow cause it has to process info in the cr2 and it has to render the segments. what it shouldn't do is load the obj 4 times for 4 segments for example. It still has to render the 4 segments so that slows things down. Since they are characters you can hide them easily till you're ready for your final render then unhide them all. A prop tends to store vertex and mesh info in the cr2 so even though 4 props are exactly the same they can be duplicated 4 times.