This may or may not the solution you are looking for, but I will try anyway

Personally, I would put these into the programme with the correct duration- if its going to take a day, put it in as a day and resource appropriately. then link it to the preceding activity, so it has a start point, and a successor. If it needs to take place on a certain day (which from your question, it doesnt appear to) then you can use a "must start on or after" constraint. If necessary you can give it a "must finish on or before" constraint it is has to be done by a certain date, although a correct successor would also do that.
this will allow you to allow a correct duration and resourcing (and thus work) to the individual task (the meeting).

I would tend not to over allocate a duration, as this can give rise to more problems ifthe meeting drops back from its earliest point, and leads to other tasks being pushed out. As a rule of thumb I would almost always give a task a correct duration and resource to an activity as this gives a better reflection of its effect on other activities.