Solution-wide launchSettings.json - visual-studio

Question

I was wondering what currently the best practise is to gain a solution-wide strongly-typed launchSettings.json inside a solution with web projects (aspnetcore 2.0).
For a single project this doesn't really seem like a problem.
However, for a solution with 3 web projects (client/api/sts) this does seem possible/easy thing to do.
The reason for me asking this is that, for example, the client needs the applicationUrl from the sts and api. The same applies for the sts and api, they all need to know each others location. This combined with a changing applicationUrl for different profiles makes it look like that I kinda have to hardcode magic strings for the urls everywhere. Thus not allowing a single source of truth.
launchSettings.json (currently: x3 -> per web project, goal: 3 urls being reused)
{
"iisSettings": {
"windowsAuthentication": false,
"anonymousAuthentication": true,
"iisExpress": {
"applicationUrl": "http://localhost:5000/",
"sslPort": 0
}
},
"profiles": {
"IIS Express": {
"commandName": "IISExpress",
"launchBrowser": true,
"environmentVariables": {
"ASPNETCORE_ENVIRONMENT": "Development"
}
},
"BuildStuff.Client": {
"commandName": "Project",
"launchBrowser": true,
"environmentVariables": {
"ASPNETCORE_ENVIRONMENT": "Development"
},
"applicationUrl": "http://localhost:5000/"
}
}
}
Thanks in advance, guidance in the right direction is all I seek.