How to group multiple rows into a comma separated column

Hi Experts,

I have a requirement where i have to convert multiple rows into one comma separated column based on some columns values. We can not achieve this with Reverse pivot transform because i am not aware how many items i am going  to get for 1 set. Kindly suggest me how to achieve this via Data services.

Source looks like :

Target should be like :

Thanks in advance,

Subbu.