Take these precautions if you set up a remote Group List as a target for a Network Delivery Mailbox:
Do not send messages to a Group List that includes a Network Delivery Mailbox whose target is the mailbox you sent the message from.
Make sure that you do not have any Group Lists that send messages to each other through a Network Delivery Mailbox. For example, a Group List that contains a Network Delivery Mailbox that forwards the message to another Group List. This Group List also contains a Network Delivery Mailbox, and this Network Delivery Mailbox forwards the message back to the original Group List.
If you set up a Group List where either situation happens, a loop occurs where a single message can generate many copies of the message.