expression
regarding; as for; in respect of
A highly formal, polite expression used in business or official contexts to introduce a topic concerning a respected person or organization. Often follows 皆様, お客様, 貴社, etc. It is a set phrase, not a productive grammatical pattern.
皆様におかれましては、ますますご清栄のこととお喜び申し上げます。
I hope this letter finds you all in good health and prosperity.
貴社におかれましては、益々ご発展のことと存じます。
I trust that your company continues to thrive.