Change Ringtone for Partner 18D

[ga6]

My office has multiple Partner 18D phones and if anyone is not at their desk when it rings I need to get up to find out which phone is ringing.
Is it possible to differentiate them somehow, such as by different ring tones? Or is there another way to differentiate them?
Thank you

[thiel2]

No, unfortunately, the only possibility is unique ringing on a per LINE basis, not per extension (and that is only available on R6 and higher)