Hello everyone,

I have an issue. I built a model with a set of regions (45 countries). But in my results I would like to aggregate some countries so that I can have both outputs by country and / or by region. Let’s take this example.

```
Set r countries /A, B, C, D, E, F, G, H, I, K, L, M/
```

Now I want to create the following set rg whose elements are in set r as follows :

```
Set r countries /A, B, C, D, E, F, G, H, I, K, L, M/
rg regions /R1, R2, R3/
```

With R1 (A, B, C) R2 (D, E, F, G) R3 (H, I, J, K, L, M).

I have tried this:

```
Set r countries /A, B, C, D, E, F, G, H, I, K, L, M/
rg2 regions /R1, R2, R3/
rg(rg2, r) aggregated regions
/R1. (A, B, C)
R2. (D, E, F, G)
R3. (H, I, J, K, L, M)/
```

But this is a two dimensional set. Normally, I wanted something like rg(r) so that from a parameter like

```
Parameter
Cost(r) ;
```

I can display the results for cost(r) or cost(rg) knowing that in rg, R1 would take the sum of A, B, C contents, R2 the sum for D, E, F, G and so on.

How, can I adress this issue?

Thanks in advance for your help.