Sharing intranet & Internet DB server

We're in the process of developing a pilot intranet application. We also have the goal of soon providing dynamic web pages for access over the Internet. A proposal has been made within our organization to share a single Informix database server between the 2 types of access--intranet and Internet. We currently have an Altavista firewall between the Internet and our network and at this point have not allowed any access from the Internet to our internal network. Just wondering if anyone else has or will try this setup and if there are any opinions or suggestions about it. Thanks.