Glue items in list

[b.fedonin]

Hello everybody! I need to know if there any way to glue (and group) items in sublists.
The result must be like “П1,В2,К2”. Thanks in advance!

[robert12546358]

Can you show full graph??

[b.fedonin]

Ok, question is off. Its strange that i didn’t found this node in the first place