RULE 12-106 WILL NOT ALLOW THIS, HOWEVER RULE 3030 WILL ALLOW IT IN CERTAIN CONDITIONS. CEC 20TH.EDITION 2006
Without knowing more details it is hard to determine whether or not this is in violation of 12-106. As long as the circuits are not derived from different systems you MAY be ok.
I think rule 3030 from Yorky's post was a typo as Section 30
has to do with lighting.Most likely meant 12-3032?(Or 12-3030?)
I am still using the 19th edition of the CEC so there may be slight differences.