REPORT - table group only shows the row 0

Hi everybody,
I’ve a report and a table group, the child table only shows the row 0 when, on details table, the property Page break = 0.
Otherwise, if I put Page break = 1 I have all rows but in diferent pages.
How could I unify it in order to have all rows on the first page?¿
Thanks in advance,

I founded that my problem were on the size of shells:
Too much space for each row!