For the purpose of claiming the home owner grant, you can have only one principal residence.
If you own more than one home, you can't designate which one is your principal residence.
Your principal residence is the usual place that you make your home. It’s where you live and conduct your daily affairs, like paying bills and receiving mail, and it’s generally the residence used in your government records for things like your income tax, Medical Services Plan, driver's licence and vehicle registration.