What I'm actually trying to find is: The metric for a massless string coming in from +infinity on the z axis, holding a spherical mass (with angular momentum) a fixed distance from the origin, along with another string coming in from -infinity on the z axis also holding a spherical mass. In addition to the metric, I'm curious what the tension in the strings are. Is there already an exact solution like that? A friend recommended Plebanski–Demianski solutions which can involve broken strings, so could possibly contain the solutions I am curious about. This paper, http://arxiv.org/PS_cache/gr-qc/pdf/0511/0511091v1.pdf discusses some very general solutions. Unfortunately, I don't understand the terms well enough to follow the discussion. What physically is a NUT parameter? Also, I must be missing something because the metric in equation 5 looks time independent, so I don't understand how it could describe accelerating blackholes. What do expanding and twist mean in this setting? is it just accelerating and angular momentum respectively? Any help understanding that article would be much appreciated.