Dynamic list in netlogo - list

Question

I was unsure how to title this question, if somebody knows a more specific title, I'm happy to change it
I'm trying to develop a model in netlogo for my thesis where turtles buy water from 18 different wells. Each of the turtles has its distance to the individual wells stored in the breeds-own variable(s) adist_w_1 ,adist_w_2, ... etc.
What I want to do is model the consumption decisions of commercial establishments by first calculating the price of water (constant + x*adist_w_y), then figure out what the demand is at this price and subtract the demands at cheaper wells from this specific well.
price = 0.75 +0.15 * distance;
individual_demand_at_well_x = f (price_at_well) - demands_at_cheaper_wells
What I've done so far to this regard looks like this:
to calc-price-at-well
set earlier-demands 0
ask commercials [
let price_w_1 ((adist_w_1 / 1000) * 0.15 + 0.75 )
let price_w_2 ((adist_w_2 / 1000) * 0.15 + 0.75 )
let price_w_3 ((adist_w_3 / 1000) * 0.15 + 0.75 )
let price_w_4 ((adist_w_4 / 1000) * 0.15 + 0.75 )
let price_w_5 ((adist_w_5 / 1000) * 0.15 + 0.75 )
let price_w_6 ((adist_w_6 / 1000) * 0.15 + 0.75 )
let price_w_7 ((adist_w_7 / 1000) * 0.15 + 0.75 )
let price_w_8 ((adist_w_8 / 1000) * 0.15 + 0.75 )
let price_w_9 ((adist_w_9 / 1000) * 0.15 + 0.75 )
let price_w_10 ((adist_w_10 / 1000) * 0.15 + 0.75 )
let price_w_11 ((adist_w_11 / 1000) * 0.15 + 0.75 )
let price_w_12 ((adist_w_12 / 1000) * 0.15 + 0.75 )
let price_w_13 ((adist_w_13 / 1000) * 0.15 + 0.75 )
let price_w_14 ((adist_w_14 / 1000) * 0.15 + 0.75 )
let price_w_15 ((adist_w_15 / 1000) * 0.15 + 0.75 )
let price_w_16 ((adist_w_16 / 1000) * 0.15 + 0.75 )
let price_w_17 ((adist_w_17 / 1000) * 0.15 + 0.75 )
let price_w_18 ((adist_w_18 / 1000) * 0.15 + 0.75 )
let demand_w_1 5 * price_w_1 ;DUMMY! include demand function of price
let demand_w_2 5 * price_w_2
let demand_w_3 5 * price_w_3
let demand_w_4 5 * price_w_4
let demand_w_5 5 * price_w_5
let demand_w_6 5 * price_w_6
let demand_w_7 5 * price_w_7
let demand_w_8 5 * price_w_8
let demand_w_9 5 * price_w_9
let demand_w_10 5 * price_w_10
let demand_w_11 5 * price_w_11
let demand_w_12 5 * price_w_12
let demand_w_13 5 * price_w_13
let demand_w_14 5 * price_w_14
let demand_w_15 5 * price_w_15
let demand_w_16 5 * price_w_16
let demand_w_17 5 * price_w_17
let demand_w_18 5 * price_w_18
let demand-list (list demand_w_1 demand_w_2 demand_w_3 demand_w_4 demand_w_5 demand_w_6 demand_w_7 demand_w_8 demand_w_9 demand_w_10 demand_w_11 demand_w_12 demand_w_13 demand_w_14 demand_w_15 demand_w_16 demand_w_17 demand_w_18)
foreach sort demand-list
[
let cheapest-well item 0 demand-list
set final_t_dem (cheapest-well - earlier-demands)
set earlier-demands (earlier-demands + cheapest-well)
set demand-list remove cheapest-well demand-list
]
]
*whereas earlier-demands is a global, final_t_dem a commercials-own
This hopefully yields the cheapest well and reiterates until all wells are "treated". But now I'm clueless as to how I can extract the information which well gets which demand from individual turtles and, this is the goal, to sum them up.
In the end, I'd like to be able to say that commercial xy has an individual demand of x for well 1 and all commercials together have a demand of y.
I'd be glad to get advice and since I'm new to netlogo also an idea if this is a smart way to go with regard to model efficiency. Many thanks!