Donald Trump -- Univision Employees Will Be Stopped at the Border ... Of My Golf Club

Donald Trump wants a wall erected -- not at the U.S./Mexican border -- at his fancy Miami golf course, and he's making anyone working for Univision persona non grata.

Trump wrote a letter to the Prez of Univision, saying "Please be advised that under no circumstances is any officer or representative of Univision allowed to use TRUMP NATIONAL DORAL, MIAMI -- its golf courses or any of its facilities."

The Donald also included instructions to "stop work and close the gate" that is being built between the neighboring properties.

Trump is amping up his attack against Univision after the network pulled the plug on his Miss USA pageant. TMZ broke the story, Trump plans to sue the network for hundreds of millions of dollars, claiming the 5-year-deal was iron-clad.

Trump ended his letter by promising if he's elected president he'll erect a "meaningful border ... not the laughing stock that it currently is."