boat sharing

We sail a small handicap fleet every Sunday. It is not uncommon for
people to sail different boats throughout a series. An example might
be that someone does race one in his laser, race two in his mates
lark etc. I cannot work out how to enter all the results for the
individual regardless of boat. We use the PY system. Everytime I
enter a different boat I end up chaging the results of the previous
race as sailwave thinks that all the races were sailed in the same

any help gratefully recieved