formating csv file for quick access of list of integers

I want to read in lists of integers in OML. I figured that I might use a csv-file for it. 

The data is organized in set ids and contains a varying number of integers, for exampe a set id 100 could be

set 100 = 1 20 30 44 500 1234

and maybe set 556 could be

set 556 = 12000 33456 120000 140000 160000

 I am still rather free how the data is written into csv-file as I am writing from a Tcl-routine running in Hyperview/Hypermesh, so I could be like:

100       556

1           12000

20         33456

30         120000

44         140000

500       160000

1234

first row would be defining the set id and the rows below in the same column define then the ids belonging into the set. However this is a little bit tedious to write from tcl, it would be easier if I transposed it, but the problem might be then the line length as the number of ids can be rather high. I could write one set

over multiple lines:

Here set id 100 would be over two lines, set 200 needs only one line and 300 would be over 3 lines. I would then only need to concate the lists together, but I am not sure how to accomplish that in oml.

Can somebody give me a tip for a handy one-liner, I tend to think the last csv-format would be easiest to write from tcl but how do I combine the id lists from successive lines, in the end I might prefer to have something like:

set(100) = [1;2;3;4;5;6;7;8;9;10;11;12;13]