Joining text with some conditions

Hi, I have a problem with joining text - little bit complicated. Please take a look at attached file.

Let's say there is Main data column which repeats same values, sometimes 3 sometimes 5,6 or more times. Each entry has its own subdata value.

My goal is to join all subdata in one cell, depending on main data.

I have tried with TEXTJOIN but I would need to adjust Main data range every single time (sometimes it is 3 cells, sometimes 5,6 or more).

Any idea on how to automate it? At the end I need to merge and center it, it would be a big bonus if it could be automated too depending on number of main data cells.

=concentate(A2,” “,A3,” “,A4)

E2=IF(MATCH(A2,A:A,)=ROW(),TEXTJOIN(" ",,IF($A$2:$A$200=A2,$B$2:$B$200,"")),"") press control+shift+enter keys to 执行。 then copy down.