Reveal Invisible Units to Opponent

Is there a method whereby the invisible counters of one player can be revealed by moving the other players counters to within a certain hex-range? For example;

In a naval campaign, an important element of play is air-searches of the surrounding ocean to locate enemy ships, or an ASW ship finding a submarine.

What I would like to be able to do is as follows;

  1. Each side moves its naval counters on a strategic map and they are all invisible to the opponent.
  2. Whenever one or other sides counters move to within a certain range of an enemy counter that counter is automatically revealed.

Example 1:

Side Red has an air counter. Its search radius is 20-hexes. As it moves across the map board, any enemy ship within that radius are detected and become visible.

Example 2:

Side Blue has an anti-submarine capability. The range of this is 5-hexes. If an invisible enemy submarine falls within this range, it is detected and becomes visible.

I have looked at the invisibility trait and read the forums. Both appear to suggest that it is not possible to achieve this capability using the Invisibility trait… so, how can it be achieved?