  An isospin-selfconsistent pn-continuum-QRPA approach is formulated and
applied to describe the Gamow-Teller strength distributions for
$\beta\beta$-decaying open-shell nuclei. The calculation results obtained for
the pairs of nuclei $^{76}$Ge-Se, $^{100}$Mo-Ru, $^{116}$Cd-Sn, and
$^{130}$Te-Xe are compared with available experimental data.
