Senator Ted Cruz (R., Texas) has invited Donald Trump to attend a September 9 rally against the Iran deal, but other 2016 presidential candidates who want to join might not receive the same courtesy.

“Two other presidential candidates called me — they didn’t call me directly, their top aides called me — asking if they can speak and I simply referred it to Ted Cruz. It’s really not appropriate for me to make that decision since they’re all competitors,” says Morton Klein, the president of the Zionist Organization of America, which is helping organize the rally at the U.S. Capitol, when reached for comment Monday.

Cruz announced that he had invited Trump to speak at the September 9 rally on Thursday, whereupon representatives from two of “the most prominent of the people running” asked Klein if they might also attend. Klein says he passed the requests to the senator and his senior staff.