  It is increasingly important to understand, in detail, two-pion correlations
measured in p+p and d+A collisions. In particular, one wishes to understand the
femtoscopic correlations, in order to compare to similar measurements in heavy
ion collisions. However, in the low-multiplicity final states of these systems,
global conservation laws generate significant N-body correlations which project
onto the two-pion space in non-trivial ways and complicate the femtoscopic
analysis. We discuss a model-independent formalism to calculate and account for
these correlations in measurements.
