There may be multiple subgroups that are pairwise permutable complements

From Groupprops

Statement

Let n be any natural number. Then, there exists a finite group G with subgroups H1,H2,,Hn such that Hi and Hj are Permutable complements (?) in G for any ij.

Proof

Let p be a prime such that p+1n. Let G be the group Z/pZ×Z/pZ: in other words, G is an elementary Abelian group of order p2. G has (p+1) cyclic subgroups of order p, and any two of these are permutable complements.