It looks as an unmaintained feature, that I requested to a developer long ago, and it was working once in a while in a developement version (before 9.x or 10.x was released, I guess). But the feature might have been unfinished. I don't really know whether it really worked in any released version of Tiki.
Can you try with Tiki 9.x, 11.x, and for sure, with Tiki 12.x? You can use the demo installations at http://demo.tiki.org
If it works in any version but not in newer ones, then you can add a bug report about it tagging your report as "regression", specially "12.x regression", if it doesn't work in 12.x either but it does work in 9.x or so.
Addidiotnally, you can add a wish as a pure "wish", that some developer finishes that feature.
Or you can hire a consultant to do that for you.