  We study general features of three-meson bound states using the Y(4660) as an
example. Here the Y(4660) is assumed to be either a two-body bound state of the
f_0(980), itself a bound state of K and Kbar, and the psi'= psi(2s), or a
three-body bound state of psi', K, and Kbar. In particular, we investigate in
detail the interplay of the various scales inherent in the problem, namely the
f_0 binding energy, the Y binding energy, and the K-psi' scattering length.
This allows us to understand under which circumstances the substructure of the
f_0(980) can be neglected in the description of the Y(4660).
