just a thought, as i am greener than grass when it comes to splicing, but could you somehow build it like this:
splice an xring into tenex, essentially making a whole whoopie sling. then, the best way i can describe it is to create a short dead eye sling with a XRR in the eye, and bury that into the main portion of the whoopie as well, resulting in both rings ending up at the same spot, then stitch it all together.
this is probably something totally wrong to do, but its a thought i had.
-Steven