In this paper, we propose a new formulation for the blind source separation problem for audio signals with convolutive mixtures to improve the separation performance of Independent Vector Analysis (IVA). The proposed method benefits from both the recently investigated convolutive approximation model and the IVA approaches that take advantages of the cross-band information to avoid permutation alignment. We first exploit the link between the IVA and the Sparse Component Analysis (SCA) methods through the structured sparsity. We then propose a new framework by combining the convolutive narrowband approximation and the Windowed-Group-Lasso (WGL). The optimisation of the model is based on the alternating optimisation approach where the convolutive kernel and the source components are jointly optimised.