I have a data sheet with 5000 items, and a user sheet with three drop-down
cells (data validation/list). When the user selects the first list, I want to
use that value to populate the second two lists. I've set up formulas so that
I know which rows (value in column A) *should* be in each of the two child
listboxes (all "true" rows go in list 1, all "false" values in list 2) based
on the user's first selection. What I haven't figured out is an efficient way
to grab 5000 values in Column A based on a value in another column, and
actually transform that into my two data validation lists (efficiently)

Example with 6 records:
Sasha True
Bobbi False
Carl False
Gus True
Drac False
Claire True

All 5000 records need to end up in either list 1 or list 2, and still have
the workbook responsive enough to be usable (not spending extensive time
recalculating).

Any ideas on how to use the true/false values in column B to populate the
data validation lists, as efficiently as possible? I can't use VBA because
the workbook will be widely distributed and not all users will enable macros.
Based on the level of user sophistication, I'm also avoiding things like
having them switch to the data sheet and sort it after making their first
selection- I'm really looking for a formula/named range formula/ data
validation formula type of approach, but I'm at a loss for how to get these
non-contiguous values into the data validation list.

Thank you!!
Keith