Thank you DaveC!
I managed to find out that it was possible to put Zones in different groups using the below URL command:
http://os-ip/cs?pw=xxx&g0=1&g1=1&g2=1& etc… g10=255
So there for example: “g0” is Zone 0, “g1” is Zone 1 etc where I put all Zones 0-9 to Group 1.
Then I put Zone 10 in Group ID: 255 which can run in Parallell independently of Zone 0-9.
So Zone 0-9 will run sequentially as usual. Let say the total time here is 50 minutes.
Then I have just put Zone 10 to run for 50 minutes. So the valve opens and closes when the program is running.
I tried it out today in the water system and it did work out.
Thank you for your help!