Can Visual Studio Application Settings have a value which refers to another Setting's value?

Can Visual Studio Application Settings have a value which refers to
another Setting's value?

For example, I've got Properties.Settings.Default.Foo which has some
string as its value, and I'd like to define another setting, let's call it
Bar, to be (some_string + Properties.Settings.Default.Foo).
I cannot find a way to do this with the Visual Studio settings designer.
Is it possible?
Thanks!