for best results
i use an external video editing program
and render my poser movie out as an image sequence
that way i can render a time span ( range of frames ) as blocks

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set up yout 2 or more cameras the way u want them for the animation....
render out a range of frames for active camera ( camera you hav on at time of render )

for example you have 100 frames

you want 60 on camera 1 ... render1 ~ 60

then switch to camera 2

render 61 ~ 100.....switch cameras then render next frame range

and so forth...
........
use external video editor ( blander 2.62 for example) to edit the frame clips ( put them together ) then render in a video format ( .avi, .mov, .mp4 ........)