You can use a splitter on the adapter.
What kind of handsets are you using?
Cordless handsets will work as per normal, with the cordless base station plugged into the hub's phone socket.
Wired handsets on telephone extension sockets around the home need VM to modify your phone wiring to run from the hub's phone socket. VM should do this free of charge for you as part of the switchover process.
Welcome to our Community Forums! Thank you for your first post and for your new landline connection query.
I can see that @goslow already assisted you with your question.
Please let us know if there's anything we can do to help or assist in making this Home Phone Switchover process as easy as possible for you.
New around here? Check out the do's and don'ts, in our Community FAQs