if its a website, you can use the JS SDK and pass down a string, and then redirect to that url - or just code in the two variations

eg:

if (gb.isOn("my-feature")) {
  window.location = someurl
}

or something like

const flagValue = gb.getFeatureValue("my-feature", "");
if (flagValue.startWith("http")) {
  window.location = flagValue;
}

just be careful with the cases - a variation with an extra redirect may perform differently just by having one more redirect