Collecting 'Daily' and 24 hr Data on the same contract

["Mike Gallagher" <mg11@xxxxxxxxxxxxxx>]

Our stock index has a high-volume Day session , followed by a
low-volume 'Night' session - much like the eMini S&P

Unfortunately my feed supplies both Daily & Night data under the same 
symbol - How do I collect  Daily data & 24 hr data in separate files ?

Cheers