Generally, depending on the Digital Voice solution that you are provided with, if these are three DECT handsets using the same base station, there won't be a problem. However, if they are separate phones connected via internal wiring (which would need to be changed a bit), it could be an issue depending on their combined REN value.
The TalkTalk Community has now moved to a peer-to-peer support model. This means that the TalkTalk team will no longer be here to support with queries. Don’t worry, there are plenty of ways to reach out if you need to speak to TalkTalk directly. For more details check out the link here
How to contact TalkTalk Broadband - TalkTalk Help & Support
