It's actually not that hard...
Step 1. You need your dataset to include a few extra columns
;with data as
select GroupName,ArticleNumber,Subject,row_number() over(PARTITION BY GroupName order by ArticleNumber) as rn
where Subject <>''
select TOP 200
rn, -- used for sorting the output
((rn-1) / 10) %2 as col_no, -- works out which column to put the data into : 0 or 1 (based on page size of 10 - this could /should be a parameter )
((rn-1) / 10) /2 as page_break -- works out which "page" within the group to put the data on (based on page size of 10 - this could /should be a parameter )
Step 2. Create a Tablix report with "GroupName" on the Page section and ArticleNumber and subject on the details section (you can include the other columns for now so you can see it is working, but remove them later for production)
Step 3. You now need to tell the report how to paginate, so go into the outermost group properties (you would have an outer grouping called list1_GroupName if you were doing this with my data) and add the dataset column "page_break" to the group expressions so you are grouping by GroupName and page_break.
Step 4. put a filter on the "detail" tablix so that it only displays where "col_no" = 0
Step 5. Select any textbox that could expand due to overflow of data and uncheck the "Allow height to increase ?" setting. (otherwise your report will not line up nicely)
Step 6. Select the outer Tablix (called List1 if you used the wizard) and make it twice as wide.
Step 7. Copy the inner/details Tablix and paste it into List1, then position it right next to existing one (side by side)
Step 8. Edit the filter on the new (2nd) details tablix so that it only displays where "col_no" = 1
select geometry::STGeomFromWKB(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orum Etiquette: How to post Reporting Services problemsForum Etiquette: How to post data/code on a forum to get the best help - by Jeff ModenHow to Post Performance Problems - by Gail Shaw