It's been a while so this is off the top of my head but you can destroy several entities from one script
You do however need to be on top of your level design and build the entire area first that you want to destroy behind you.
For example your first area contains 1000 items .
Place the player marker after the items to destroy so your not including this, (not sure it would cause problems but better safe than sorry) then destroy all these using the following script in a trigger zone.
function destroyall_init(e)
end
function destroyall_main(e)
if g_Entity[e]['plrinzone']==1 then
for x = e-999, e-1 do
Destroy(x)
end
ActivateIfUsed(e)
end
end
You can also use batches of any '- ' number if you want to destroy more zones behind the player.
This way you keep it tidy and don't need a bunch of item numbers.
If I am wrong then I am sure someone will be along to correct me