Multiple Rhythms?

I only just got the notation program the other day, so I don't want to say this doesn't exist, but I've looked all over and can't find a way to allow conflicting/multiple rhythms on the same staff. In other words, I want the treble clef to have a whole note played on Beat 1 along with a quarter note, then the whole note is sustained through Beat 4 as a dotted half note is played on Beat 2 and then sustained through Beat 4. Is that possible with this software? Am I missing something?