A mounting system for facilitating ordered mating of plural connectors includes a first plate having plural mounting positions for first connectors. A second plate is attached to the first plate by a standoff. A housing extends between the first and second plates and substantially covers an area between the first and second plates. In a keying embodiment, each mounting position has an inner perimeter shape different than the others. Each connector of plural first connectors includes a threaded portion holding a first nut with an outer perimeter having a shape unique as compared to the other first nuts. The outer perimeter of the first nut seats into one, and only one, of the plural mounting positions. A third plate is mounted to and spaced from the first plate. The third plate includes plural keyholes which are aligned to the plural mounting positions. Each keyhole has an inner perimeter shape matching the inner perimeter shape of the mounting position to which the keyhole is aligned. The keyholes only permit a second connector, with a matching key nut, to pass therethrough and mate into the first connector in the aligned mounting position.