Can I ‘stop’ registration on an Event when it reaches a certain number of participants?

*Update – This relates to Connect 8 only, the Connect Events registration tool in Connect 9 has the capability to limit registration*

There is not really a way to ‘stop’ registration for an event, but a couple of things you might consider (and test in a non-production environment as these might be somewhat ‘subjective’ in their effectiveness)
Firstly, if the event is set that registrants ‘require approval’ then it is relatively easy to just ‘decline’ people over and above the 100 limit, the mail sent to the ‘declined’ registrants can be customised to maybe include a link to register for the next event.
If the approval/decline option is not used then you might also try changing the mail sent to registrants when they are ‘approved’ after you reach the 100 limit to say ‘apologies, this event is full’ and change the body of the text to remove the ‘login here’ text and replace that with ‘click here to register for a future event’.  I *think* this should be reasonably clean.
Note – the process to count to the ‘100 registrants’ is manual, not something Connect Events can do

Note – there are alternate registration solutions for Connect that can limit registration more effectively