basically my map is set to CP mode... with the intel set to koth, setting it to koth was the only way it wouldn't end the map after 3 captures. as for the sounds, I think some of the outputs on the item_teamflag that valve gave us would make my system simpler. Basically on pickup of the intel, I use triggers to see which team picked it up, then use my soundsystem to play the correct sound for each team (since the sounds were absent since it isn't on ctf mode)
question, are you wanting to have to hold the intel at the capture zone for 5 minutes BEFORE they can cap? or do they cap it then hold for 5 minutes?
if its before they can cap, I would suggest putting an inaccessibly capture zone under the capture area, so they are pointed to it, and can see they are there, but can't cap it... then have a trigger multiple that is filtered to the intel (might have to use a logic_measurement_movement to move a func_physbox in relation to the intel, if filtering for the intel doesn't work), this trigger multiple onstarttouch starts the timer and onendtouch pauses the timer. On the item_teamflag dropping the intel pauses the timer. At the end of the timer, enable another capture area above the hidden one, that they can access.
I think that should do it...
if they cap then defend, its even easier, parent the intel to a moving platform that moves it under the ground so you can't get to it, after you pick up the intel, move that platform down. Onreturn of the item_teamflag raises it again, but it won't raise when it's captured, so once they capture it they can't get it again. after it is captured, switch ownership of a cp to the attacking team, and start the timer. if the defenders can reclaim the cp by the end of the time, then they win.