Which resurrection group was left to cover after the church-age believers?

Les teaches that the last several programs covered the resurrection chapter, 1 Corinthians chapter 15, beginning with Christ and the firstfruits, since He was the first to be resurrected, along with those who came out of the graves after His resurrection in Matthew 27. They then looked in depth at the resurrection of the body of Christ, the church-age believers, and how they will be separated from the rest. That left one group still not squeezed into the previous four programs: the resurrection of the Old Testament believers. Les explains that the best place to pick that up is back in Daniel. Before going there, he reads the verse used as a jumping off place for the resurrection of believers of all the ages, 1 Corinthians 15:23, where every man, that is every believer, is raised in his own order or group: Christ the firstfruits, afterward they that are Christ's at His coming. He notes that Scripture does not lay it all out in that one place but instead sends readers back to other portions to dig out where the various groups of believers come into play regarding resurrection.