Getting Yum to install from selected repository only

Working from Using Yum to local install without checking Repository, you can use the same principle to install from selected repository while disabling the rest.

# yum --disablerepo=* --enablerepo=dag install (packages)

where dag and update are repositories. If you are not sure the repository names to use, go to /etc/yum.repos.d/xxx.repo. The first line [.....] is the repository names