These private or office-exclusive listings exist for sellers who want limited exposure, often for privacy reasons, and they are legal, but they also mean fewer buyers see the home, and the seller may leave money on the table from reduced competition even after the usual 4 to 6 percent in closing costs is accounted for.
Your own buyer's agent can call around to other brokerages and ask specifically whether an off-market or exclusive listing exists that matches your criteria, which is a normal and routine request in the Saskatoon market.
A private network listing is a real thing here, but it is reached through a phone call between agents, not a public search. Get your hand-reviewed valuation from Joel Dyck.