Reply feature for a users within a distribution list

Question

We need to have the following feature when a user respond to a mail which he received as a member of a distribution list.
To allow ‘Read’ only access to all who are currently in the group ID and restrict ‘Respond’ to only the 3  names?
When any of the 3 names respond to the email, the signature should read ‘xxx desk’?
Many thanks
Shiva

Answer 1

Thanks for the reply  .
Please check my response below
1. You can restrict the list so it only accepts emails from the 3 authorised users with the mail delivery options.   -We need this group to receive mails from the internet.So any user should be able to send to this group
2. This is more complicated, but with a transport rule whenever one of the 3 authorised mailboxes send to the group in question, you can append (like a disclaimer) text to the end of the email.  Unfortunately it goes at the end of the email, and not
at the end of the part of the email just added to the chain, but if the signature is that important, it might do.   -The users will be responding to the mails which they receive from external senders ..they also respond to other mails using their
personal ID ..so when they send using their personal ID the signature should not be the same ..
Shiva
So to be clear on the requirements:
The list needs to accept email from the internet
Only a certain group of users should be able to reply internally to that group
When they reply to that group, a generic signature should be used instead of a personal one
Have we understood correctly?  if so, then the solution proposed by Deepak would seem to be the better fit, but I think you would be better to alter the process to one which is more easily managed.
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