I think the following schedule will work.
(A G) (B H) (C I) (D L) (E K) (F J)
(B C) (J G) (D E) (H I) (F A) (L K)
(K J) (C D) (G H) (E F) (I L) (A B)
(E L) (F K) (A J) (B G) (C H) (D I)
(F I) (A L) (B K) (C J) (D G) (E H)
(D H) (E I) (F L) (A K) (B J) (C G)
because of the symmetry, it doesn't matter which way around the rows and columns are assigned to rounds and events. Mathematically this is known as a Howell Design (http://mathworld.wolfram.com/HowellDesign.html).
Here is a special schedule for an all-plays-all round robin with the property that rounds 1 to 8, or alternatively rounds 8 to 15, considered separately are both solutions to your 8 event problem.
rnd E1 E2 E3 E4 E5 E6 E7 E8
1 (A N) (G D) (H J) (B L) (K P) (C M) (I O) (E F)
2 (E O) (C K) (A P) (F I) (L J) (N B) (M D) (G H)
3 (P B) (F O) (G C) (M E) (D A) (K H) (N L) (I J)
4 (M J) (N P) (D B) (C H) (E I) (G O) (F A) (K L)
5 (I C) (A H) (O L) (D P) (B F) (J E) (G K) (M N)
6 (L G) (M I) (K E) (J A) (N C) (D F) (B H) (O P)
7 (F H) (J B) (N I) (K O) (G M) (A L) (P E) (C D)
8 (D K) (E L) (F M) (N G) (H O) (I P) (C J) (A B)
9 (J P) (O A) (E H) (I K) (M B) (L C) (D N) (F G)
10 (N E) (P F) (L D) (A C) (J G) (M K) (O B) (H I)
11 (O M) (B C) (P G) (H D) (F N) (E A) (L I) (J K)
12 (G A) (K N) (C O) (E B) (I D) (F J) (H P) (L M)
13 (H L) (D J) (I A) (P M) (C E) (B G) (K F) (N O)
14 (B I) (H M) (J N) (L F) (A K) (O D) (E G) (P C)
15 (C F) (I G) (B K) (O J) (P L) (H N) (A M) (D E)