It is narrated from Sayyiduna Ibn Umar (may Allah be pleased with them both) that the Prophet (peace and blessings be upon him) said: No one should send a marriage proposal over the proposal of his brother until the first proposer leaves it or gives him permission.
Hadith Referenceمسند احمد / مسند المكثرين من الصحابة / 6036
Hadith Gradingحکم دارالسلام:إسناده صحيح ، خ: 5142، م: 1412.