This is the first time I read someone asking for this type of feature, although it would be actually interesting to automate the reviewer designation process, which is definitely quite tedious, but rather necessary.
It should be possible, but OTOH it would be seem quite a complex undertaking, lots of variables to account for (profile, bio, interests, availability - which is only defined during the designation process), automation of email sending.
I haven't heard of anyone customizing OJS this way.
I believe that an international reviewer database and service would be required in order to make this work more appropriately, in order to centralize the reviewer data and its integrity and quality, as well as making it a more generic service, available to any peer-review process, not only OxS.
Ramón Martins Sodoma da Fonseca
Analista em C&T
Coordenação de Tecnologias de Informação
Instituto Brasileiro de Informação em Ciência e Tecnologia - IBICT
Ministério da Ciência e Tecnologia - MCT