  In this paper we construct new solutions of the Einstein-Gauss-Bonnet field
equations in an isotropic Shiromizu-Maeda-Sasaki brane-world setting which
represent a couple of $Z_2$-symmetric vacuum thin shells splitting from the
central brane, and explore the main properties of the dynamics of the system.
The matching of the separating vacuum shells with the brane-world is as smooth
as possible and all matter fields are restricted to the brane. We prove the
existence of these solutions, derive the criteria for their existence, analyse
some fundamental aspects or their evolution and demonstrate the possibility of
constructing cosmological examples that exhibit this feature at early times. We
also comment on the possible implications for cosmology and the relation of
this system with the thermodynamic instability of highly symmetric vacuum
solutions of Lovelock theory.
