According to JDN, an avreich asked Rav Chaim Kanievsky an interesting question about matanot la'evyonim - the tzedaka we give to the poor on Purim.

This fellow wanted to accomplish killing as many birds as possible with one stone - he asked Rav Chaim Kanievsky if it is possible to give one's donation for matanot laevyonim to the Vaad Harabbonim tzedaka organization and at the same time submit his name to be included in prayers at the graves of Mordechai and Esther in Iran? Perhaps he would be required to make a second donation for that purpose and not double up on one donation?

Rav Chaim paskened that one could give matanot laevyonim to the Vaad Harabbonim and also say the donation is for the merit of healing someone and doing other things with the donation does not in any way lessen the hiddur of the matanot laevyonim aspect of it. As a matter of fact, one fo the "bnei bayit" later confirmed that Rav Chaim himself does this very thing.