Maybe something like this:
Manipulate[
If[choice != oldchoice,
oldchoice = choice;
sample = Partition[10 choice Range@6, 2];
Pause@3
];
sample[[part]],
{{choice, 1, "Sample choice"}, Range@10},
{{part, 1, "Part of sample"}, Range@3},
{sample, ControlType -> None},
{oldchoice, 2, ControlType -> None},
TrackedSymbols :> {choice, part}
]
