Youtube sync between 2 accounts

Hi again,

I have two youtube account one personnal, the other for my androidtv.
I want to synchronize one way videos from a playlist (personal) to an androidtv playlist .

I do not know how to handle this properly with current nodes.
I want to

  1. browse target video lists IDs,
  2. keep the list,
  3. browse source video list to check if in target list, if not add it to a list ‘toadd’
  4. loop in some way to add the id in the target list

I know there are Function and Function Item node, how can I store list between nodes ?

thank you