Allow people to be members of more than one virtual team

We have a flat organisation structure where people may belong to multiple teams. For example, they may be working on two projects at the same time, or they may be in the sales & marketing team as well as the management team, or management & finance. 

It would be really helpful, particularly when looking at the impact of clashing leave requests, for people to be in more than one virtual team, so we could see the impact on, say, the board & management or sales & management of a holiday request without having to just look at the entire company as a single team, which is what we have to do at the moment.