Straight table formatting

[timmy]

Hellow

I have a question to format a straight table.

I have a straight table with look like this

Dim1 exp1 exp2 exp3 exp4

now, i want on expression 4 a concatenated formatting of a field called "Stockplaces" in my datamodel.
So, making a long story short. How can i concat the values of stockplaces wich will be found for my values in dim1

the format needs to be like this: place1,place2,place3

Greetings

Timmy