[AccessD] Totals on a crosstab query

The xtab in question lists horses on the rows and lesson types on the
columns (i.e. private, semi-private, group), then populates the columns with
counts for the number of lessons per horse per lesson type. No problem so
far. But the specs call for vertical totals of the columns, and I cannot
figure out how to do them with the xtab wizard. What I need is a sum of
each of the columns to be presented as the bottom row (i.e sum of private,
semi-private and group columns, including all horses).

Any suggestions gratefully accepted.

Arthur