Button problem

hello there…
i’ve a problem…

im in movieclip 1… i have 4 buttons…
when you press one of those buttons i want to go
to frame 30 in movieclip 1 (this is no problem…) he will play till
frame 50 and then stops… this will be for all buttons…

now… for example i pressed button 2…(it will go to frame 50 from 30)
but when it reaches 50 it has to go to movieclip 2 frame 2…

when i press button 3 it has to go to frame 50 and after that to movieclip 3

etc etc…

does anybody know what kind of actoins i have to give to the buttons and frme 50???

thanx