Are multiple text fields in a number format possible?

Using Excel 2019, I'm trying to use a cell's custom number formatting to display, say
6,050,001,000
as
6B 50M 1k

Is this possible? I've found a way to make the format conditional, so it will display one of the three dynamically, but I'd rather show the full string if I'm able to. Results I've found seem to suggest you can only have a single text field in a custom number format rather than multiple.