Concatenate rows into one row by value of a column

Hello,

I am trying to concatenate several rows into one row, so several cells in same column but different rows should go into one cell. The grouping should be done by the value of another column.

Here is the data. So all the values in cells C2, C3 and C4 (same item - "XZR") should be concatenated into one cell - C20. The same is for each of the items ("XZR", "AWE" and "TUP"). Please note that I need to show them in a separate lines within the new cell (so I also need to concatenate them with a line break, as shown in the example). 

I appreciate your help!

Thanks,

Eyal