  We introduce an exactly solvable model for interacting bosons that extend up
to high spin and interact through a repulsive pairing force. The model exhibits
a phase transition to a state with almost complete $sd$ dominance. The
repulsive pairing interaction that underlies the model has a natural
microscopic origin in the Pauli exclusion principle between contituent
nucleons. As such, repulsive pairing between bosons seems to provide a new
mechanism for the enhancement of $sd$ dominance, giving further support for the
validity of the $sd$ Interacting Boson Model.
