QUARTILES in Excel

[Francisco]

I was wondering there is a simple way of not applying linear interpolation
within QUARTILE and PERCENTILE formulas in any version of Excel.
We work in salary surveys and it is mandatory to pick up an existing figure
from a DataSet.
To ilustrate an example, from a dataset of 8 salaries, we use the 3rd salary
figure as the lower quartile and the 7th figure as upper quartile.

The ideal scenario will be to have a 3rd parameter within QUARTILE where it
is possible to specify:
1. (default) linear interpolation
2. no interpolation, pick up the next discrete value
3. no interpolation, pick up the previous discrete value

Thanks in advance.
Francisco