I have 20 people attending a conference over 3 days. Some are coming for only a portion of the meeting, but I need to know how many will attend each session.

I have arrival date & Time in column L and the departure date & time in column Q. I have the date & time for lunch in cell B2.

I have a formula that will calculate if the attendee is arriving BEFORE the lunch:
=IF($L4=0,"0",IF(L4<$B$2,"1","0"))

But as the week goes on, some people will leave before the next lunch, so I really want it to look at the arrival and departure dates (L4&Q4) and determine if B2 falls in between. I tried, with no success:

=IF(L4=0,"0",IF((L4&Q4)<$B$2,"1","0"))