No you can't. When you sign the contract with a agent, it always in it. He would be the only agent. None agent would accept your business if you say you would use multiple agent at same time.
The is case for both buy selling house and renting house.
If you never renting house before, it is best for you hire a agent to rent your house. Because they know how to check the background of the renter. In ontario the law is not on landlord side, it is very difficult to get ride of bad tenant.
Ottawa Rental agents for list of renting agency.