  A new strongly correlated electron model is presented. This is formed by two
types of sites: one where double occupancy is forbidden, as in the t-J model,
and the other where double occupancy is allowed but vacancy is not allowed, as
an inverse t-J model. The Hamiltonian shows nearest and next-to-nearest
neighbour interactions and it is solved by means of a modified algebraic nested
Bethe Ansatz. The number of sites where vacancy is not allowed, may be treated
as a new parameter if the model is looked at as a t-J model with impurities.
The ground and excited states are described in the thermodynamic limit.
