How to setup a send-only email address on iPhone

I have some email accounts (gmail, yahoo, etc.) that are forwarded to a primary address. I have that primary address configured in iOS mail, but need to "send from" those other addresses. I have to resort to my desktop Outlook application where it is simple to setup those as "send-only" addresses. Any way to do this on iOS, preferably in the native Mail app, but willing to consider another app. Setting up a POP mail account on iOS with dummy incoming mail settings is not a good option, I've tried and that just hangs Mail for a long time when checking for new mail, even if I set the account to "manual" fetch.