Support for different currencies in database fields

(Not sure whether this should be a question or a suggestion for app improvement.)

When creating a new number field in database, there are a few options to format the number, namely "Number", "Number with commas", "Percent", followed by a bunch of currencies (US Dollar, Yuan, Euro, Pound, Yen, Ruble, Rupee, Won, Canadian Dollar, and Franc).

Is there a way to add custom format for these numbers (especially for missing currencies)? For example, I'm using Thai Baht (e.g. ฿1,234.56 or THB 1,234.56), but this option is missing.

(Using a workaround of using other format is not viable as my table contains multiple currency columns, and using the wrong format would just be confusing.)

If there could be such a flexible way to add custom symbols or ISO 4217 three-letter code, that would be awesome! Or if there is a way to do this already, please inform me.

Thanks!