This list and autoresponders

I am currently trying to start a mailing list for psychologists in Denmark, 
and I have been told there may be a huge problem with autoresponders, that 
is: Someone has his or her mail program send for instance the message: 'Out 
of office, will be returning monday'. And then this message wil start a 
loop and be resent every time it is sent back to the person (or to other 
persons using autoresponders)

Since it is not a problem with this list, can anyone tell me: How does this 
list handle this problem? Is it necessary to use a special program or what?

Sincerely

Jan Ivanouw