[Therion] Hide symbols within certain maps/subsurveys

[Tarquin Wilton-Jones]

Hi folks,

I have a survey of a cave and its surrounding surface area, including
all the little caves in the area. So you can basically get an overview
of the area, see the surface streams and sinks.

Normally, I want the cave survey to be on its own, showing the cave's
features, passage names, fill areas, boulders, water flow, etc.. But
when I show the area overview, all those features become unimportant,
and most labels should be hidden (only the cave names are important).

When showing an overview though, I still want to show the surface
labels, slopes, cliffs, water flow, arrows, borders, etc.

Does anyone have a nice way to hide almost all symbols within one
map/subsurvey (the cave), while showing them all within other maps (the
surface)? Does Therion have a dedicated way to do this that I missed?

Cheers,

Tarquin