How to create a team when the team won't turn up?

Yesterday I had a lunchtime meeting with the team that focussed around team building. There have been some rumblings from staff in the program that other staff are not pulling their weight and that a small number of staff are shouldering the burden of the other staff and 150 students on their own. In order to try and start building capacity in the team, I decided that we needed to get some lunchtime meetings (where lunch is provided) happening in order to get the conversation happening. We started with a Y chart on which everyone wrote their own personal ideas on what their ideal BYTES class looked like, felt like and sounded like. Once each person had done this, we combined responses on to one chart, which is now pinned up in my office as a reminder. We talked about the things that we needed to see improved and then each team member was given an individual goal setting sheet that asked them to imagine the words they would speak, the actions they would undertake etc if they were contributing to making this 'ideal' a reality. But here is the problem when you are working with staff. Of the 15 staff in the team, (and despite the three weeks notice) three couldn't come because of sporting committments, two could only come for half the meeting because of yard duty (I knew about that when I planned the meeting - it couldn't be helped) and one just forgot. Another turned up late after telling me he was definitely going to be there. What do you do about that sort of thing? It is frustrating because the meeting was organised a long time ago and these other things just "came up." It is frustrating because you put a lot of effort in (including buying food and drink) and some people don't bother to contribute. It is frustrating because one of the new staff that I was particularly trying to target because he is a classic "watcher" and not a participator was one of the ones that didn't turn up because of 'other' committments. Just like he often leaves the after school meetings early because he has family committments. It is difficult. I don't get a say in the staff who are in my team - the timetabler decides who she can fit in and people get to indicate their interest on their allottment form. This means that this year almost 1/2 the team are new, and this 1/2 of the team have been timetabled on together so they can't even learn from the experiences of others because they are all new. In the other 1/2 of the team there is not one single new person so they automatically work much better than the other team.
I guess this is one of the issues with dealing with busy people in a school environment. In an office it is expected that everyone turn up for their meetings so you can target the group as a whole. In a school, everyone has so many other committments to do with school that often they have things on that mean that they have to miss a meeting. It makes it hard to build that team spirit if there isn't a team there to build. I guess I have no choice really but to keep on plugging away. My goal is to now get them thinking about the type of skills we want to promote in our students in this program and then audit the curriculum with this is mind, improving, adding and making what we do stronger. I will continue and hopefully by the end of the year there will be an achievement to write about.