i18Next: use locale only for some languages and use language + location for rest

I have a question for the i18next library. If I have these set of locales that are possible to be detected from the browser,

de
en-US
es
fr
it
ja
ko
pt-br
zh-cn
zh-tw

Is there a way to configure it where it respects the language only for some locales and not the other? for example, when it comes to en-US, I wish for the loaded language to be en so when I call the .language or .languages method, it will contain en instead of en-US. However, for the other locales that have a dash like pt-br, zh-cn, and zh-tw, they will remain untouched, (so NOT return just zh).

Is this possible?

thanks in advance!