Heh, well the only way I can think of doing that easilly is to get rid of the frag grenade's timer and detonate it with a rocket or something along those lines.
i was thinkin about a ce map of the battle field 2 map gulf of omen and i need the c4 and cant makin the needler shoot 4 to 5 grenades and then they would blow up when u reload? that could work couldnt it?