Filter based on couples of parameters

[Rosanero4Ever]

Hi all,

In a report of mine, I need to perform a filter using a multi select prompt value (and this is ok...)
For each selected value, user must specify a number corresponding to the selected value because this number is useful to a calculation which consider the selected value and the relative number
So, I would filter using a structure similar to an HashMap<Value, Number>
This is simple when user select a single value and a number in a text prompt.
In a multi select context users can select multiple values and for each value must they assign number in order to perform the correct calculation for each selected value

how can i develop this prompt?

I hope my explanation is clear..

Many thanks in advance for your time.