MILP-using if conditions in the sum

[Yahialion]

Hello all,
I have a parameter set c(i,j), where i index is for origin addresses and j is for destination addresses. It represents the cost for delivery between those pairs.
Also, I have d(i,j) which represents a demand parameter set from i to j.

However, there are fixed set of employees assigned to cover each origin that will be assigned to deliver based on the delivery cost,

for example if the cost is between 5 USD and 10 USD, and origin i=a, then there are 5 js and their i.ds: (1, 2,3,4, and 5). And we have five drivers (uaa,bb,cc,dd, ee) will cover when delivery costs threshold are (<2, 2-5,5-7,7-10, >10). All five drivers have demands [de(1), de(2), de(3), de(4), and de(5), respectively] that supposed to be fulfilled and when a driver's demand de(r) is full, then the demand will be added to the demand of the following driver

My question: is there a way to formulate a constraint (if conditionals over other set): that says when c(i,j) belongs to a delivery cost threshold, then sum d(i,j) < de(r)?

Please advise,

Thanks

[bussieck]

I don't get. Instead of many words do more math/example code and some concrete example.

-Michael