joining text into one cell

I would like to join text from different cells into one cell. This is for Google sheets. I tried concatenate and join. But they don't seem to work. I realize that it can be done using the & function but it would bea drawn out equation since I have multiple multiple cells to join.

Sample spreadsheet. ..

A B
1 john 2321
2 Cindy 5543
3 Bob 4665
4 Mike 5543
5 Sean 4356
6 Vince 5543
7 Walter 6667

I would like to know the formula to combine all the instances of 5543 into one cell. For eg. The outcome would be VinceMikeCindy

Solved! Thanks so much. Was not familiar with the filter function.