Campaign module with concealed armies/scouts

Hi all.

I wonder if anyone can help with this: I am currently working on a campaign map idea to generate terrain for tabletop wargames. This as an alternative to throwing dice and randomly plonking down hills and forests on the battlefield.

The idea is this: two armies, represented by two counters, and several scouts, also represented by counters, enter at opposite ends of a campaign map, with a square grid. Initially all one side’s scouts and army are invisible to the other side. Scouts, however, who enter the same square as the opponent’s army, see that army (which remains visible thereafter) but are not themselves revealed to the opponent. An army that enters a square occupied by an opponent’s army reveals that army and is itself revealed. The square occupied by the 2 armies becomes the battlefield: the terrain indicated in it is replicated on the tabletop, and the orientation is decided by which side the second army entered the square.

Scouts do not reveal other scouts.

The idea is to find and track the opponent’s army, whilst avoiding revealing one’s own army until one has found the right terrain to give battle.

Question is: how does one do this in VASSAL? I’m grateful for any advice.