How do I aggregate/concatenate values from columns into one row (and set filter)

You are absolutetly right. Please apologize:

how do I create the "new value" in this example:
>As you can see I have a table with Dimnsion VALUE, which contains ABC and DEF, these are connetected by the field ID. So I need to establish a connection between these two independant data sets based on the ID=1. so the first three columns is the data available to me and the last column "new value" is what I am hopping to calculate.
So someting like New Value = concat(VALUE) linked/aggregated by ID

and more advanced how do I get "NEW VALUE IN" and NEW VALUE OUT" in this example?

> this takes the idea from above one step futher:
Again I have only data available from column 1, 2 and 3. And I am trying to calculate column 4 "new value in" and column 5 "new value out"

I need to connect the "values" based on "ID" and filter them based in the "Index". Here I need to connect each value with the "value" within the "ID" but in a different way:

so something like :

New Value In = concat (value) linked/aggregated by ID only for INDEX where INDEX-1

New Value Out=concat (value) linked/aggregated by ID only for INDEX where INDEX+1

I hope this makes it more clear.