This is a little harder than
20 couples. I would like to arrange it so that no pair of couples meets a second time until round 6, but I can't find a schedule like that. The schedule below has the hosting properties that you want, and no pair of couples should meet more than twice.
Group 1 Group 2 Group 3 Group 4 Hosts
(J N M F) (E I B A) (H D C L) (P O K G) [F A H G]
(N O D B) (I L F E) (M P K H) (C J A G) [B L M C]
(D C M I) (J L P B) (G E H N) (F K O A) [D J E O]
(K F E C) (L G I O) (N A H M) (P B J D) [K I N P]
(G B E M) (D A F P) (H I O J) (C K N L) [G F H C]
(L P A E) (M F G D) (O C B H) (K J N I) [E M O J]
(I N P C) (A M L O) (B H G F) (E D J K) [I L B D]
(F H I P) (A G C J) (O E D N) (B M L K) [P A N K]
1 2 3 4 5 6 7 8
----------------
A | * C O N F E L *
B | A * J P G O * K
C | H * D K * O I A
D | H B * P F M * N
E | A L * K G * D N
F | * L O K * M B P
G | * C E I * M B A
H | * M E N * O B P
I | A L D * H J * P
J | F C * P H * D A
K | G M O * C J D *
L | H * J I C E * K
M | F * D N G * L K
N | F B E * C J I *
O | G B * I H * L N
P | G M J * F E I *