Question: May Allah be good to you, this questioner asks: if a person intends to do two things, does each affair have a separate Salatul-Istikharah or does it counted for him to pray one prayer for both of these affairs?
Answer: “If a person intends two different affairs in which he is not sure he will do them both or leave them both or do one of them and leave the other, then he prays for both affairs and supplicates for both affairs. If he prays a separate prayer for each affair and supplicates for each, then this is good. Yes”
Faisal Ibn Abdul Qaadir Ibn Hassan