There are a few different synonyms for the phrase "according to purpose." One common phrase that means the same thing is "with intent," which indicates that something was done intentionally and with a specific purpose in mind. Another similar phrase is "for a specific reason," which emphasizes that there was a clear motivation behind a particular action. "In line with one's objectives" is another way to describe an action or decision that was made based on a specific set of goals or priorities. Finally, "with a particular aim" is another synonym that highlights the intentionality behind a particular action or decision.