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Lauren Sanchez Con-Grad-ulations to son Nikko ... Party w/ Ex Tony, Bezos!!!

Lauren Sanchez has the whole blended family gathering down to a science ... celebrating her son Nikko's graduation with her soon-to-be-husband, her ex and his wife!

The TV personality shared a series of photos from Nikko's college grad party, featuring Jeff Bezos, Nikko's dad -- NFL Hall of Famer Tony Gonzalez -- and Tony's wife, October. The adult squad seemed even to enjoy each other's company, posing for multiple pics together.

Mama Bear posted a tear-jerking video in honor of her boy, who's 23 now ... comprised of pics of Nikko before cutting to an emotional speech Sanchez gave during the festivities -- and, ya gotta watch it for yourself because it's LS at her most raw.

Lauren and Tony had Nikko way back in 2001 during a short-lived romance ... and, they both went on to marry other people -- Lauren to business exec Patrick Whitesell and Tony to October.

In fact ... Tony and October have been together so long, it seems she and Lauren are pretty tight too -- 'cause she posted a tribute to her stepson filled with bikini pics alongside Sanchez.

Lauren gave some credit to October on how Nikko turned out FWIW ... responding "Our baby boy!" to her post -- so, clearly she sees childrearing as a true group effort.

Sanchez has two more kids BTW ... she's shares teenagers Evan and Ella with Whitesell -- so, expect a few more teary graduation posts in the years to come. Her current fiancé, JB, has four kids of his own -- so, the very modern family's pretty massive.

Nice to see a couple of celeb exes who can get along --  'cause it doesn't always work out like that!!!

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