List of distinct categories assigned to entry

Question

I need a NON-duplicated list of distinct Category Names assigned to a range of entries.

-- Show non-duplicated list of (CAT GROUP 2) for Entries --

Summary:
- Products are assigned to TWO categories (one in Group 1 and one in Group 2).
- I have a page that displays a list of all Entries (Products) in Category A (Group 1).
- I want to display a non-duplicated list of Categories from Group 2 that are assigned to the range of selected Entries.

I was hoping to do this without using {exp:query} or a plugin.

Crappy Code Example:

{exp:channel:entries channel='products' dynamic='no' category='{segment_2_category_id}' category_group='1'}
    {categories category_group='2' style='linear' backspace='2'}
        {category_name} <!-- Category Name unduplicated -->
    {/categories}
{/exp:channel:entries}

NOTE: This question might be a duplicate of: Show categories associated with a list of channel entries