Private chat with signalR and angular

I'm using signalR to create a message chat private between customer and admin(for customer support)

The customer will be a mobile app sending a message to admin will be a web app(I'm ok with that). But now I want if Admin1 send to customer the message will show in Admin2 screen

Two method to customer send message to all admin, and admin send private message to specific customer

public async Task AdminSendMessageToCustomer(ChatHubRequestModel requestModel)
{
    await Clients.Client(requestModel.ConId).AdminSendMessageToCustomer(requestModel)
}

public async Task CustomerSendMessageToAdmin(ChatHubRequestModel request)
{
    await Clients.All.CustomerSendMessageToAdmin(request);
}

You guys can give me some keyword to find out, Tks for your time