  A general fusion method to find solutions to the reflection equation in
higher spin representations starting from the fundamental one is shown. The
method is illustrated by applying it to obtaining the $K$ diagonal boundary
matrices in an alternating spin $1/2$ and spin $1$ chain. The hamiltonian is
also given. The applicability of the method to higher rank algebras is shown by
obtaining the $K$ diagonal matrices for a spin chain in the $\left\{ 3^*
\right\}$ representation of $su(3)$ from the $\left\{ 3\right\}$
representation.
