There's two ways you can do this.
1) Create a sub-OU under the server OU for those five servers and move them into it. Then assign the policy you want them to have after breaking inheritance.
2) Create a group for those five servers in ePO and move them into it. Then break inheritance and assign the policy. Keep in mind, you can not be enforcing sync with AD and have this work. The servers will simply be moved back into their assigned OU.