The function you mentioned:
!(A or B) = !A and !B
is the same as:
A or B = !(!A and !B)
So let's start by splitting your problem into two parts of ABC and DEFHRP.
(A and (B or C)) = (A and !(!B and !C))
(D and E and (F or H or R or P)) = (D and E and !(!F and !H and !R and !P))
Since these two parts are joined by an 'or', we can apply the equivalence again to get:
!(!(A and !(!B and !C)) and !(D and E and !(!F and !H and !R and !P)))