In Jabir's detailed account of the Prophet's Hajj, he prayed Dhuhr and Asr together at Arafah with one adhan and two iqamahs, each shortened to two rak'ahs, then at Muzdalifah he prayed Maghrib and Isha combined in the same way. This joining (jam') and shortening (qasr) of these prayers is a confirmed Sunnah of Hajj. Scholars differ over whether the people of Makkah also shorten at Arafah and Mina, but the Prophet's combining of these specific prayers on that day is agreed upon.
Evidence — the daleel
Sahih Muslim 1218 Ṣaḥīḥ
On deen2u
Informational, not a personal fatwa. Consult a qualified scholar for rulings on your situation.