Require passcode for all participans in one particular meeting

Hello,

There is a page on our website where the participants of our meetings find all the different links. When they click the link they are never asked to enter the passcode. This is how we want it as many of our meetings are more open than others.

However, there are some meeting that are more restricted and my question is if it's possible to make those specific meeting require anyone who click the link to enter a passcode?

Thank you in advance.