Pretty sure you can macro the "Attacking [target]" to be said along with a mark. Regular marks still work on CC, you could just combine them. Might as well add in a regular chat message like "/p Attacking <t>!" for the macro to work outside of CC since quick chat won't work in places like Frontlines anyways, that way you'll always have a talking portion of the macro AND a mark over the head of the target you just called out.