How have you declared the amounts transferred to your wife / mother's sister / mother? Is it a loan or gift, etc?
You can club only yours and your wife's income in your hands. Your mother cannot club the loss of her sister. Further, clubbing may not be allowed by the assessing officer, unless you prove completely that it was your income which was traded in your wife's name. And once you start clubbing, you will have to club even in the years in which there is a profit earned by your wife.
A better position will be to show the profit / loss in each of your return and carry forward the losses and set it off against the future years of profit.
M.Com., CA, LL.B