Hi just in the process of putting up a new plasterboard ceiling in my kitchen and i want to put up 50w recessed downlighters(6 in total 2 packs of 3)into the plasterboard, my questions are i already have an old light which i want to take down can i just connect the new lights onto this and use a junction box to connect the other three lights so it gives me the six i want,also are these downlighters ok into plasterboard?.My last question i have a single switch which turns the one light on but i want to be able to either turn on all six lights or three if i want ,what would i need to be able to do this.