Giving a full list a fixed height

You can “hide” a full list by putting it in a popup like this. Then maybe refer to that fully/loaded “source” by making your visible repeating group based on a list of numbers as described on this post/video (which could also be inside cell 1 of your scrolling group. Its the only way I know to avoid “double” loading, maybe there’s another way I don’t know. Not in front of computer at moment.