  A novel experimental scheme enabling investigation of transient exotic spin
couplings is discussed. The scheme is based on synchronous measurements of
optical-magnetometer signals of several devices operating in magnetically
shielded environments in distant locations ($\gtrsim100$ km). Although
signatures of such exotic couplings may be present in the signal from a single
magnetometer, it would be challenging to distinguish them from noise. By
analyzing the correlation between signals from multiple, geographically
separated magnetometers, it is not only possible to identify the exotic
transient but also to investigate its nature. The ability of the network to
probe presently unconstrained physics beyond the Standard Model is examined by
considering the spin coupling to stable topological defects (e.g., domain
walls) of axion-like fields. In the spirit of this research, a brief ($\sim 2$
hours) demonstration experiment involving two magnetometers located in Krak\'ow
and Berkeley ($\sim 9000$ km separation) is presented and discussion of the
data-analysis approaches that may allow for the transient signal identification
is provided. The prospects of the network are outlined in the last part of the
paper.
