How to send message to both groups A&B

[listenYes]

Hi

Can I think so,if subscription address is identical in multiple nodes,then they are a group?

If so:

the light_1&light_2 OnOff Server Model subscription address is 0xC001,So them is in group A.The group A address is 0xC001.

the light_3&light_4 OnOff Server Model subscription address is 0xC002,So them is in group B.The group B address is 0xC002.

Now,I have a button,I want to use that control the groups A&B(light_1&light_2&light_3,light_4).But There's only one publication adderss (OnOff Client Model publication adderss is only one).What should I do?

Adds 0xC003 to light_1&light_2&light_3&light_4 OnOff Server Model subscription address,Equivalent to Create a adderss=0xC003 of group C.The button sending message to  destination address=0xC003?

OR

The button multicast to group A and group B for using  virtual address?But I don't know how to use virtual address.

Or there's another way?

[haakonsh]

Go with the first option.
Create a new group address that all OnOff clients subscribe to. I believe that is what you describe in:

"Adds 0xC003 to light_1&light_2&light_3&light_4 OnOff Server Model subscription address,Equivalent to Create a adderss=0xC003 of group C.The button sending message to  destination address=0xC003?"

[listenYes]

Create a new group address that all OnOff server subscribe to.The OnOff client send message to this group(the message destination address was the new group address).

[haakonsh]

Yes, exactly. I ment to say "Create a new group address that all OnOff servers subscribe to."

[listenYes]

Have to create a group C include the group A&B?And not using the  virtual address(such as the virtual address Implicit inclusion the group A&B address)?

[haakonsh]

Sry for the late reply.

You need to create new elements in each device, the new elements will be a copy of the old ones, Create a new group address for the new elements and subscribe/publish to it. 

[listenYes]

sorry,I don't quite understand what you mean.If in a old device have one element(OnOff element),according to you,the device have to twos element(OnOff_1 & OnOff_2)?(my English is so bad,sorry)

[haakonsh]

I'm afraid I've given you bad information, you do not need multiple models/elements! 

Your light bulbs(OnOff servers) can subscribe to multiple addresses. This means that you need to configure Light 1 and 2 to subscribe to address 0xC001 and 0xC003, and Light 3 and 4 address 0xC002 and 0xC003. 

The master switch(OnOff Client), that you want to control both groups with must be configured to publish to address 0xC003. 

Sorry for the misinformation :/