It would be a great feature if the BONUS:SPELLCAST tag can accept SCHOOL=Text as its 'x' parameter. There are closed content sources which enable the modification of number of specialty spells.
KNOWNSPELLSFROMSPECIALTY and SPECIALTYKNOWN can only be used in class lines.
Other method is to let the KNOWNSPELLSFROMSPECIALTY to be used in ability lines.
BONUS:SPECIALTYSPELLKNOWN|CLASS=x;LEVEL=y|z is now in place for 6.01.07 +