SAN MATEO — The family-owned Hillsdale Shopping Center in San Mateo has brought a big-time real estate investment firm on board as a partner in the busy Peninsula retail hub, the companies announced Tuesday. The Bohannon family originally developed Hillsdale Shopping Center and opened it as an outdoor mall in 1954. Now, the family is bringing in Northwood Investors, a real estate private equity firm, as a partner in the 1.3 million square foot retail complex, which operates on 47 acres. “We are committed to continuing our family’s relationship with this property and its service to the San Mateo community as we have done for the past 75 years,” said David…