How to render strands split into Front and Back passes

[dwigfor]

I would like to split my simulation into 2 passes; Front (+Z) and Back (-Z). I need to insert a 2d image inbetween the 2 passes in After Effects. I can do this with straight particles, but I'm not sure how I'd do it with Strand Trails. I'm still not that comfortable with strands...

I'm guessing I would need to create 2 new strands, 1 for the half in Positve Z, 1 for the the half that's in Negative Z. Any ideas would be welcome!

Thanks,
-Dave