Multiple connection to one user?

Hello. Please tell me, I use Workerman in my web application to send server notifications to clients. I don't understand how to solve this problem:
The user came from a PC, logged in to the site and connected to the web socket via a link like this:
wss://mysite.com:1234?Username=User.
Then he logged in to the site via phone, and I allow the previous session on the computer not to end.
Therefore, he has the same link where Username=User.
But notifications are sent only to the last connected web socket.
It is possible to union connections with one Username?