Exchange 2003 Front End Question

I have an existing Exchange 2003 environment with 2 Exchange Servers. Both host OWA and OMA. I wish to install a Front End Server in this environment. If I create a 3rd server, install Exchange, and then make it a Front End Server; will this break anythingn in my existing environment? I would like to do this and do some testing but I am concerned that selecting the Front End option might screw something up in the production environment.

Thanks