Yes, I was thinking a bit about it. There are two possible variants. Technically both need a a second database field.
One variant is like it's done for the speaker: two individual fields and you (or the layout) decide which one you want to show where. This needs also second field in the editing form.
The other variant is like it's done for the Joomla articles. There you can set a "readmore" line, which then splits the content internally and shows either only the intro or full text (but not only the second part).
I tend to the first variant, so it's similar to the speaker. Imho it also allows a bit more flexibility.
