Executor refusing to pay remaining inheritance

My father passed away at the start of 2011 and had made a will with a Spanish lawyer and my aunt is the executor. The will was completed in June 2011 and my aunt only gave us part of the inheritance and is refusing to pay the remaining monies to my brother and I unless we agree to sell the property that was left in his will to the three of us, however it was never stated in the will by Father's will that we had to sell the property. Does the executor have the right to insist this condition?