Measure to combine multiple columns for filtering

Hi again, I'm sorry to re-respond, but that link you provided.. I just found myself more confused when I started working with it. When people fill out their entry form, they can choose from a list of hazards, which are each columns in my table.

While each hazard has its own column, there is also a column records this 'generic' hazard as a record. Ie: vehicles, uneven ground, etc.

I was able to create a new table from these responses somehow, but I'm not sure if it helps:

Now, in my main table, as I said there is a column header for each 'generic' hazard. In those columns are all the 'specific' hazards that people can choose from. Here is an example below:

I'd like to create a slicer, somehow. Something that lets me choose a general hazard and then shows me all of the specific hazards within that general hazard that people have entered. I can't figure out how to make them all work together.