  Studies of scattering amplitudes for electric and magnetic charges have
identified previously overlooked multiparticle representations of the
Poincar\'e group in four dimensions. Such representations associate nontrivial
quantum numbers (known as pairwise helicities) with asymptotically separated
pairs of particles, and thus cannot be described as tensor products of
one-particle states. We extend this construction to sources and spacetimes of
higher dimension. We first establish the dynamical origin of pairwise helicity
in $p$-form electrodynamics coupled to mutually nonlocal branes. We then
interpret this pairwise helicity as a quantum number under an $SO(2)$ pairwise
little group associated with pairs of distinct branes. We further characterize
the "higher" little groups that could in principle be used to induce
multiparticle or multi-brane representations of the Lorentz group.
