Sky router just for VOIP

[Jaish]

Is there anyway to use a third party router for the FTTP connection and managing the whole network and only hook up the sky router for the sake of having the VOIP line?

I'm finding the S203 router inadequate for my needs as I have so many devices and won't even let me assign a different DNS and I'm having to do that at device level.

[TimmyBGood]

@Jaish 

Yes, but for that to function the Sky Broadband Hub / Max Hub has to be the gateway device connected to the ONT, with the additional router behind it.  This does inevitably create a double-NAT because Sky router hardware hasn't got a 'modem mode': whether that's an issue depends on your own network use.