How to create parallel interactions in a sequence diagram using plantuml

Question

Hi i want to make a uml diagram with some parallel interactions like this, using plant uml.

But i don't know if it is possible to add the dotted lines between the 'threads'. What i have so far is the following. A is sending something that is picked up and acted on by b, c and d at the same time. Is it possible to add dotted lines between b, c and d?

group par
  activate a
  a -> b: doSomething

  a -> c: doSomething

  a -> d: doSomething
end

Answer 1

You can add the else keyword to separate the threads :

par
  activate a
  a -> b
else
  a -> c
else
  a -> d
end