title: Google sheet array formula + Join + Filter
body: <p>Does anyone know how I could expand the join+filter with arrayformula?
  I need it to automatically expand instead of sliding the formulae into new rows.</p>
  <p>Tried to search this problem but couldn't find a solution for myself.</p>
  <p><a href="https://docs.google.com/spreadsheets/d/1b0x_gapgmts9GHModQViIL7IpGmLmCfmmrrDvd1MaQ0/edit?usp=sharing" rel="nofollow noreferrer">Copy to sheet itself</a></p>
  <p>Problem in question highlighted in orange.</p>
  <p>Thanks a lot!</p>