Can a single domain be installed onto 2 servers, one of them running Zimbra Open Source edition another one running Zimbra Network Edition? Will this kind of install impose any limitations, e.g. shared calendar and GAL across servers?

I have 2 groups of users, under the same domain, some of them need the features of the Network Edition, the rest can just use the Open Source Edition. What is the best way to achieve this? Thanks.