Subsequent connection to multiple callees

Hi all,

I have a specific problem and would love to hear your suggestion on what’s the best way to solve it (in theory/used modules).

Requirements :
[ol][]There is one caller and 2…n callees[/]
[]the connection to the caller needs to be established at all times and his voice needs to be monitored/saved to a file throughout the connection[/]
[]for 1…n-1 the callees are subsequently called and transferedb[/b] into the connection of the caller if (and only if) they press a key during the first X seconds after they picked up the call[/]
Can I accomplish this with one .call-file and one dialplan?
Is it beneficial to use a queue/conference?

Thanks a lot,