can travel pass be used first for free MTR rides for 3 days b4 using the express train to HKIA?

hi,
My group will be coming from Guilin to HK using high speed train and will be staying in HK for 3 days. Can I purchase airport express travel pass one way in advance? and start using it on day 1 to day 3 by riding for free in mtr, then on the last day, from Kowloon, in-town check-in our luggage and ride in airport express train to airport?