Possibility of one Account that can see all Accounts?

[Yoke]

Hello,

is there a possibility to create one account, that can see all other accounts/mails that are stored in the Database?

I need it for a small group of people. Everyone has his own e-Mail-account on the same Domain, but there will
be one who must see sometimes the Mails of the others, while is on a business trip.
And it is not a good idea, to forward all the other mails to his account. Only sometimes he need some information
of the account of another one.

Thanks in advance
Markus