Currently there is no out-of-the-box way of making sequential builds in TFS, so I took a look at the REST API, that TFS provides.
Add a Powershell build step to the definition and call an inline script like this:
$TFSUri = $env:SYSTEM_TEAMFOUNDATIONCOLLECTIONURI
$project = "[Team Project]
$BuildID = [BuildID]
$json = @"
{
"definition": { "id": $BuildID }
}
"@
Invoke-RestMethod -Method Post -UseDefaultCredentials -ContentType application/json -Uri "$TFSUri/$project/_apis/build/builds?api-version=2.0" -Body $json
Note. Change [Team Project] and [BuildID] to correct values.
For more info about API see Build
