Voltage regulators are voltage sources by nature, it's unclear where the current source comes into play in the mentioned application note. I can imagine some ways, but that's just guessing.You need to show at least the referred block diagram.
The general problem of paralleling voltage regulators is that they have "too" good load regulation or in other words very low output impedance. With the unavoidable tolerances, one regulator will have a few mV higher output voltage and thus take the full load. Application notes usually suggest some 10 or 100 milliohms balancing resistors to achieve equal load share. You can't do more with usual 3-terminal regulators that don't expose internal control loop nodes.