Family regrouping is a fairly standard type of visa across Europe, intended for workers who bring their families over after they are established in the country. Normally, it is far easier to apply for the family visas at the same time that the worker is going to the country - unless, of course, the worker's visa is a "temporary" one where the assumption is made that the worker will return home at the end of the visa period.

Your best bet is going to be to speak with the Spanish consulate.
Cheers,
Bev