two phones with different extension coud ring simultaneously

[trina1]

Avaya IP Office 11.1
I have a request from a customer, where the customer has a need for simultaneous call ringing on 2 telsets when called one of the extension numbers with telephone specifications 1608 and J129 even though it is from an internal call.. Since J129 could not assign many button and if using group it should be dial the group number, but in here we need to dial the extension numbers and get the simultaneously ring.
Thanks

[markgallagher]

Use Internal Twinning.

[trina1]

Thanks Mark