SAN FRANCISCO — When Buster Posey took over as the San Francisco Giants’ top baseball decision-maker a little less than two years ago, he described his goal as nothing short of winning championships and making memories. He’d go about it by taking a lesson from what worked during the three-title era that he conducted from behind home plate.The Giants won their three World Series championships between 2010 and 2014 because of shrewd complementary signings, prescient trade-deadline additions and no shortage of stars that aligned. Primarily, though, all of those things were supplemental to what mattered most: a smartly scouted and drafted core of homegrown players who began to arrive as a trickle or two followed by a crashing wave.There was no better reminder of that lesson, and that legacy, than Saturday’s Wall of Fame induction ceremony on the shores of McCovey Cove. What do Posey, Pablo Sandoval, Brandon Crawford, Brandon Belt and Joe Panik have in common, other than owning very large, very sparkly rings?They all came up through the Giants’ system, and not just as players. As fathers and family men, too. The Giants held a pregame reception for the Wall of Fame honorees and their families at a rooftop private event space across the street from the ballpark, and you couldn’t bite into your first canapé without noticing how all the kids were reconnecting like cousins at a family reunion.“We all got to experience the ultimate high, winning championships together, watching all these guys make great plays in the field, and we also had a lot of lows together as well, and that brings you together,” Posey said. “But when I look at them, and we’ve had time to spend with our families today, that’s a big part for me — thinking back to all the times that our kids had growing up together. And to have them back here together today to share this with us was really special.”Each of the five honorees uttered a version of the same sentiment: This weekend is so cool, and what makes it so much cooler is that they get to celebrate it together.Do trade deadline deals lead to World Series rings?Joe Crisalli“I’m proud and I’m happy to be part of this group,” Sandoval said. “That means the organization gave opportunities to the young guys who came from the farm system to do all the things we did.”It didn’t happen overnight. Sandoval bounded into the big leagues in August 2008 and demonstrated right away that his bat would be just as precocious as it was against Double-A pitchers. Matt Cain and Tim Lincecum were already settling in as top-of-the-rotation presences. Jonathan Sánchez began to show the same potential albeit without the consistency, and then Madison Bumgarner teamed with Posey to form an all-rookie battery in 2010 that completed what became a championship rotation.