Apply filter to exclude certain rows from PERCENTILEX calculation

I have a sales dataset and am trying to use the PERCENTILEX.INC function to identify certain percentiles (25% and 75% quartiles specifically). Due to some outliers and noise in the data, I want to exclude certain records. What I'm wanting to do is apply a filter, say exclude groupings where [Sales] < 1000, and then apply the percentile function on the remaining dataset. This will ensure the percentile quantification is only focusing on data that I want it to. One challenge is the filter needs to be applied on an aggregation, meaning the base data needs to be aggregated up to a column and then filtering needs to be applied.

For example,

The percentile (and filtering of data) needs to be applied on:

I've tried numerous iterations to created a summarized table, etc. Below is my lastest:

VAR AggTable =

SUMMARIZE(FactTable, Fact[Item], "AggValue", CALCULATE([Sales], FILTER(FactTable, [Sales] > 1000)))

RETURN

CALCULATE(PERCENTILEX.INC(AggTable, [AggValue], 0.25), ALLEXCEPT(Item, [Category]))

Thanks.