match part of url, to either of the provided phrase or word, without making it optional

[ThetripGr]

Hello , i need to do something like the following but i can't seem to get the syntax right or something.

Flight::route("/$langRegex/a-url-part|another-url-part(/@permalink:[0-9a-z\-]+)", function ($permalink) {
   //...rest of code
});

so how I need this to behave ->

1. First match the languange (a simple e[nl] check )
2. Then i want to match either a-url-part or another-url-part
3. Then look for the optional parameter inside the parenthesis, that's after either of the options before

i tried /$langRegex/(a-url-part|another-url-part)(/@permalink:[0-9a-z\-]+) this kinda does work but it makes the (a-url-part|another-url-part) part , optional which is something i do not want because then any url with just /$langRegex/ will match on this route.

Is there a way to make this work with just the syntax or a regex , without duplicating the block of code?