Short message layout schedule

Is it possible to program a layout for less than a minute?in the sense that: I wish I could send a running message at a certain time, and the message is only 15 seconds for example.
inserting the message in a layout and then going to program it, it is possible to set only within a minute (example 20:15 at 20:16), and this is repeated for the whole minute.
I don’t know if I managed to explain myself well, but how can this be solved?
thank’s!