Sayyiduna Samurah (may Allah be pleased with him) narrates: The Prophet (peace and blessings be upon him) forbade a man to send a marriage proposal over his brother's proposal, or to make a sale over his brother's sale.
Ahmad recorded it; its chain contains Imran bin Dawar al-Qattan, whom Abu Hatim and Ibn Hibban declared thiqah (trustworthy), while Abu Dawud and others declared him da'if (weak). The rest of its narrators are the narrators of the Sahih.
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب البيوع / 6377