Need to look up and combine data

I have a spreadsheet similar to the attached example. Essentially I have the following:

Table 1: This table is a matrix filled out by a staff. For each area, there are 5 potentially relevant objectives (I say potentially because not all objectives are relevant to each area). I then have a list of documents that would pertain to that area if that particular objective applies. For example, Document A applies to area Blue objective 1 and 2.

Table 2: I want to automatically pull the values in the highlighted column based on what is populated in table 1. You can see that area Blue objective 1 only pulls document A because that's all that is marked in table 1. Area blue objective 2, however, pulls "A, B" because both A and B are checked in table 1.

I thought I could try an index and then try to find some way to combine the results but I'm having much more difficulty than I originally thought. I've also found this thread (https://www.mrexcel.com/forum/showth...(Concatenate-)) and it's close, but I'm not quite sure it fits what I need. Any help would be greatly appreciated. Thanks.