There is a little known feature of Active Directory replication called "Change Notification" which enables an administrator to override the default lowest replication value of 15 minutes between two sites. By enabling Change Notification between two sites you can drop the replication between these two sites down to a schedule of every 15 seconds.Here's how it's done:

1: Launch ADSIedit.msc
2: Navigate to Configuration
-CN=Configuration,DC=ForestRootDomainName
–CN=Sites
—CN=Inter-Site Transports
—-CN=IP

3: In the right hand pane, find the siteLink for which you would like to enable Change Notification, right click on it and select properties.

4: Find the attribute in this list titled "options", and modify the value from "" to "1?, click OK, then click Apply.
5: Change Notification has now been enabled for the siteLink.