The broken-pair model is used to study the nature of collective pair structure in even nuclei and a possible connection with the interacting-boson model IBM-2. In our selfconsistent treatment there is no particle-hole ambiguity, such as has been reported in recent literature. We find that about four particles away from a closed shell, for both protons and neutrons, the collective 2 + (D-pair) structure becomes roughly independent of mass number due to the proton-neutron force. Only near the closed shell pronounced fermion configurations show up. The same is true for the 3-(F-pair). In lighter nuclei, the 20