It takes just one person to put you in the right path in understanding Bitcoin then the rest work is left for you as if you truely want to learn about Bitcoin then you have to do further learning yourself. One person can do it alone, you must not be in groups to go and convinced someone to start investing in Bitcoin. Bitcoin is very easy to explain and more easier when they person you're teaching is educated.
When discussing Bitcoin with someone and they're not interested, you don't have to force the teaching on them, just let them be and when they're ready they'll come around. We have so many people that needs Bitcoin in their lifes as it'll make a big difference when they can earn an income to help with everybody needs.
The point lies in someone who wants to get to know bitcoin and if they know bitcoin is an investment solution that they can run then many sources will lead them to know bitcoin in detail. Today there is widespread media explaining bitcoin both on YouTube channels, Twitter and others, but they need to be able to filter the information so they don't get lost with the real information.
If after going through the discussion they are not interested then you should leave and don't try to convince people like this, because for them any information about bitcoin is not useful for them to listen to. I prefer to go through the explanation one by one for people in introducing bitcoin, but first I will see their interest in bitcoin first and if they intend to learn about bitcoin they will definitely be interested and will try to discuss anything they want to know.