adjective satellite (s)

• nearest in space or position; immediately adjoining without intervening space(adj.all)

  Example:
  Our rooms were side by side.
  

  Synonym:
  adjacent, next
  

  source: wordnet30
• closely related or associated(adj.all)

  Example:
  A city in which communism and democracy had to live side by side.
  

  source: wordnet30