I can do this using a table with three table-cells and put fo:blocks inside
area A and B for the information, however I wonder if this is the best way.

Note that the use of tables for multi-column layouts in HTML
was usually due to navigation bars and all kind of side matter.
In XSLFO you have regions for this purpose.

There are still quite a view cases where you have to use tables
in XSLFO for layout purposes. This isn't bad (and I wish they had
named it "grid" instead of "table").