Okay, but we have two parallel set of verses, both speaking of resurrections of believers, during the end of the world, at the return of Christ, both involving a set of trumpets, with the resurrection event happening at the time of the final trumpet.
I guess I’m just not seeing any good reason to believe they don’t refer to exactly the same event. It’s an unnecessary complication, because once you say the verses aren’t connected, then there must be two comings of Christ, two resurrections of believers, two sets of trumpets, etc, of which we don’t really find any evidence. Once an interpretation starts leading you through hoops like that, it’s usually a sign that you missed a much simpler interpretation that is more consistent.
Tell us what you believe ‘in Christ’ means. Upon that designation hangs the timing for their resurrection.