Distribution Lists - Separation?

[Bruce]

Summary-
I have just recently moved to a new service provider that
limits the number of email addresses in a distribution
list to 50 or number of email addresses you can send to in
one message. The purpose, which I agree with, is to
prevent spamming on a big scale.

Problem-
I have distribution lists of 500+ address.

Question-
Is there a way to separate these lists without having to
go thru the slow process of cutting and pasting every name?

Thanks,
Bruce