How is Salat al-Istikhara performed when one is hesitant between more than two matters, such as choosing between several spouses or jobs?

Istikhara is recommended when embarking on a matter with unknown outcomes. It is permissible to perform Istikhara for each issue separately, for example, by saying: "O Allah, if this job (and he names it) is good for me...", and this is preferable. Also, there is no impediment to performing a single Istikhara for multiple matters.