Excluding categories from loop (multiple selections)

Firstly, thank you for the plugin — it’s simply excellent.

I have one question about excluding categories when you have multiple selections. At present I have a gallery page with three categories:

http://www.furthereast.com/gallery/

Once a category is selected I can keep the user in the category loop with a simple ‘in_same_cat’ => true — that’s fine. The issue is that I also have another category called “front page OK” which determines the random rotation for the gallery picture of the front page (this way I can make sure no portrait orientation photographs are included).

http://www.furthereast.com/group/landscapes/

However, now that multiple categories are selected if the user selects Landscapes, for instance, the night photo of Akihabara which is in the Urban category will also appear in the loop.

I’ve tried the ex_cats and ex_cats_method terms but I can’t get it to do what I want… Is this possible with the plugin?

Thanks for the help!

https://wordpress.org/plugins/ambrosite-nextprevious-post-link-plus/