Is it permissible to combine several matters in a single Istikhara prayer, or does each matter require a separate Istikhara prayer?

Istikhara is a supplication (Du'a) in which a servant asks his Lord to choose the better of two matters. It is permissible to mention more than one need in the Istikhara after praying two Rak'ahs, by combining them in the supplication: "O Allah, if such-and-such a need and such-and-such a need are good for me...", although it is preferable to dedicate a separate prayer and supplication for each need.