I'm not 100% sure this will work, but I think you do this:
On epo1, in the General policy for McAfee Agent, go to the Repositories tab. Choose "Use order in repository list". The add epo2 to the repository list.
run a mcafee agent install from epo2 on each machine.
or I can't find the kb article right now, but you can basically stop the framework service on the client, replace a few files (sitelist.xml or sitestat.xml and others) then when you start the framework service up it will see the new details of the server and report to that one. Search mcafee kb and here in the community.
The option from HupSkiDup will migrate all clients to ePO2.
I don't think that that is what you want to do.
The best thing to do is:
Configure ePO2 to have a distributed repository of the unc or ftp type.
You can host this on the epo2 if you like.
Add the repository manually to the agent policy of clients on the ePO1 server. Make sure that you select the option use the repository list (and not to connect on ping time or subnet value) and order the repositories in the order that you like.
This is basically what jguenrdc also suggested.