Custom Locale to use for a java application

[Arbe]

I know I can create almost the Locale I want to use all over my
application. I also can get a NumberFormat or DateFormat instance from
that Locale, and use default formatting provided, or even customize
that default formatting as desired.

In the scenario I'm actually facing, I may have multiple different
formats to apply for a single Locale. For instance NumberFormat has as
available Locale fr_CA, but I might one to have different number
formatting styles for fr_CA. For that reason makes sense to use the
variant option on the Locale. Then I can have fr_CA_style1 and
fr_CA_style2. Imagine I do:

Locale locale = new Locale("fr","CA","style1");
NumberFormat nf = NumberFormat.getCurrencyInstance(locale);

That would five me the default NumberFormat for Locale.CANADA_FRENCH,
as my custom Locale is not part of the number format defaults.

The question then is, how can I customize/extend the list of available
Locales on those Locale sensitive classes (NumberFormat or
DateFormat), so when I try to get the instance I get my custom
instance?

Thanks in advance!
Albert