realtime grapping and marking

Soon iam going with the school to an event where we are going to film some sports. We are going live with it, and thats where it would be realy nice to have an application withc is able to grap 2 signals, and where it is posible to set markers on highligts wich the commentators can review after the match. It all needs to be done live, and while it is importing.
I have a mac pro so the hardware is fast enough.
Wich application can i use? I dossent have to be free.

What school do you go to?

An multimedia designer school in Denmark..
I have learned that final cut pro cant be used for things like that, but there must be an alternative..