Draw an activity across multiple swimlanes

Question

I would like to be able to draw an activity that spans multiple swimlanes. This activity is performed simultanoeously by two or more actors. 

A Definition like this:

|C|

|A|

|B|

|A|

start

|C|

|A|

|B|

:Task1|

|A|

stop

Does not produce the result that I am looking for. Any help will be most appreciated. 

Strsqt400

Answer 1

Hello S.,

Just to attempt to answer or add some elements to an old question.​

From:

You can use fork as:

or split (but a little clumsy ):

See also doc. here: https://plantuml.com/activity-diagram-beta#e94238d282a9dadb

If that can help,
Regards,
Th.