I think if it's teams, then using standard bikes is better because then the stronger riders can help the weaker riders. Lack of drafting on TT bikes could be a factor.
For this reason, having even teams in size would probably make sense, with the 'finish' time being based on the last rider to cross the line (the stronger riders in a team, therefore, gain nothing by shooting off and leaving the weak riders behind.
Taking up Chris's idea, each team could have their own 'meet-up'. So, for e.g., Lee and Marino have a meetup at say 7 o'clock, set up by Lee and only inviting Marino. Chris, Michael and Andy have a meetup, set up by say Andy, who only invites Chris and Michael - their meetup is for 7:04. Next group have a meetup for 7:04:30 with Steen, Pete and me etc etc.
A few ideas there ... could work if we have enough riders commit to a day and we can get the teams sorted. I think so long as each team's start time is based on the slowest rider, then we could even have a stronger rider in that team as we only could the slowest time (e.g. I could ride with Lee and Marino at 7, and then the onus is on me to work with the other two to get us all around the course - I gain nothing by shooting off).