the.com/old boys club

means An informal network of (usually) men who hand each other jobs, favors, and access based on shared background and personal ties rather than open competition.

from Traces to British public-school slang, where "old boy" meant a male alumnus of a particular school. "Old boys" kept in touch after graduation, and the informal networks of mutual favor they formed — in business, politics, clubs — became known as "old boy networks" or "old boys' clubs" by the early-to-mid 1900s. The phrase later broadened beyond school ties to describe any closed loop of insiders who look out for their own.