Service account setup with domain scope

I am installing a SQL Server 2014 Instance on a server in my domain. There is already a 2008 R2 Instance on a different server in the same domain. The 2014 Instance needs to:1) Run SSIS packages via the 2014 SQL Agent that have connection strings to the 2008 R2 Instance2) JOIN tables in the 2008 R2 Instance in tables in the 2014 Instance (T-SQL code in stored procedures)How should the service account be set-up for the SQL Server Agent and SQL Server?I have done this when both Instances are on the same server using the default virtual accounts. However, I don' think these accounts or the Local accounts have a domain level scope.Thx