Golang - pass struct as argument to function

I have to parse some nested JSON, which translates into a Go type, like this:

type Config struct {
Mail           struct {
				   From     string
				   To       string
				   Password string
			   }
Summary        struct {
				   Send     bool
				   Interval int
			   }
}

Now I want to call a function for each key (Mail, Summary), I tried it like this:

utils.StartNewMailer(config.Mail)

The problem is, how do I construct the called function, I tried to mirror the Mail struct (and called it mailConfig), since I can't pass an arbitrary struct as an argument.
func StartNewMailer(conf mailConfig){ //..., but that doesn't work either, I get the following compiler error message:

cannot use config.Mail (type struct { From string; To string; Password string }) as type utils.mailConfig in argument to utils.StartNewMailer

Do I have to pass in every single value to the called function or is there a nicer way to do this?

utils.mailConfig fields should be exported, as in the literal struct field in Config type.

type mailConfig struct {
	From     string
	To       string
	Password string
}

I suggest declaring inner structs as types themselves instead of using struct literals.

type Mail struct {
	From     string
	To       string
	Password string
}

type Summary struct {
	Send     bool
	Interval int
}

type Config struct {
	Mail
	Summary
}

func StartNewMailer(Mail mailConfig)