Mexican Arms Dealers
The Mexican Arms Dealers are a small-time hispanic criminal organization that only appear in one mission, Gun Runner in Grand Theft Auto: Vice City, their leader, Pedro Garcia is a rival gun seller to Phil Cassidy, presumably, in taking out Cassidy's business in gun smuggling. They have no fronts nor any territory whatsoever in Vice City but may have an allegiance to the Cholos through Pedro Garcia.
Phil Cassidy wants to eliminate his rival gun smugglers and tells Tommy Vercetti to take him and his business out by eliminating Pedro Garcia and the crates of arms on their Walton utes. Once the mission is complete, and so forth in killing Garcia, the same guns stolen from the dealers can be bought in Phil Cassidy's Place in Little Haiti. After that, The Arms Dealers disappeared in Vice.
An interesting note is that during the Gun Runner mission, gangs such as the Cubans, Vice City Bikers, Haitians and Patrol Invest Group will exchange fire with the M.A.D as they pass their turf.