HOLLYWOOD, Fla. — The head of the Republican National Committee implored leaders of his sharply divided party on Friday to rally behind their eventual presidential nominee, suggesting that they ignore Donald J. Trump’s assault on the nominating process.

Reince Priebus, the committee’s chairman, did not mention Mr. Trump by name when addressing the group’s members at the party’s spring meeting here, but he devoted much of his speech to the tensions created by the Republican front-runner.

“Now I know our candidates are going to say some things to attract attention,” Mr. Priebus said, in a barely veiled reference to Mr. Trump’s attacks on what he has called “a rigged” and “corrupt” nominating process.

“That’s part of politics,” Mr. Priebus said. “But we all need to get behind the nominee.”

Mr. Trump is not the nominee yet, but his considerable advantage in delegates and lead in overall votes has prompted some mainstream Republicans to come to terms with the likelihood that he is the favorite, however unthinkable it may once have been, to become their standard-bearer this fall.