[How] Standard game plus expansions in one Vassal module?

Apologies if this has been asked before but I did a search and couldn’t find any threads on the topic.

I’ve created a Vassal module for the standard version of a board game and I now wish to include its 3 expansions. Each expansion introduces new races (Goblins, Kobolds, etc) which in Vassal terms means additional unit tokens and additional cards for the game decks.

What I want to avoid is having to create a separate Vassal Module for each expansion because players can opt to play the standard game plus any combination of the 3 expansions so there’s quite a number of permutations.

How do I make the certain races (and hence unit tokens and cards) available or unavailable based on the expansions chosen when commencing the game within the one Vassal Module?

If it’s easier to point me in the direction of an existing Vassal Module that achieves this which I can review then that will be equally valuable.

Thanks in advance.

Create an extension for each of the supplements. Extensions allow you to add optional or supplemental items to the main module, like new maps or counters. Players can then choose to load (or not load) the extensions at gameplay time.

An overview of extensions is given in the user guide, found under the help menu.