Create rule to Forward mails without attachment

Hello guys,

We are using exchange server 2013 server. The query is as below;

1. Need to create a group ID called abc@abc.com and add 5 mailbox members into it.
2. The group ID will receive confidential data in excel format from our client on daily basis. The requirement is that the mail should be forwarded to those 5 members without the attachment.
3. One of the member will login to the web-mail of the group ID and download the attachment for further work.
4. In case if there is no e-mail received, then a mail should be generated with the message "there is no mail received from the client or client's ID" and it should go to those 5 users.

1st point is already done. i need help for 2,3 & 4th points. don't know how to achieve it. Please help.

Thank you

Shiv.

Shivkumar