It's not completely clear what you are trying to achieve, but you might be
able to do something like

{ ASK SectionAStart }

then the following nested field (all the {} eed to be the special "field
braces" you can insert using ctrl-F9) for the first Section

{ SEQ SectionA \r{ REF SectionAStart } }

then the following field for all the rest:

{ SEQ SectionA }

If this doesn't make any sense can you try to spell out what you want in a
bit more detail, preferably with more examples?

Peter Jamieson