How to Flatten a Row without string concatenation

[JEC]

Basically, I am filtering projects based on the attribute, 'Additional project managers'.

I understood that we can flatten a row in sql by concatenating the data into a string.

For example:

The issue with that is when I filter by using "John" on the Additional Project Manager string field, the result won't come up.

I understand that this is due to wildcard matching in string and I need to type in "*John" in order to make it work.

Thus, I wonder if there's another way to flatten a row. For example, is there a data structure that works like a set in Python? So that the order of data does not matter and I can filter by "John" and this project will come up.