A connector set comprising a connector element for use in a flashing assembly for roof windows mounted side-by-side comprising at least two flashing members each having a leg intended for being arranged so that it projects away from the window frame, where the connector element has an exterior side intended for facing the exterior in the mounted state, an interior side intended for facing the roof in the mounted state, a first end intended for facing the window, a second end intended for facing away from the window, two side walls extending between the first and second ends and forming a gutter extending in a longitudinal direction and being open towards the exterior side, and at least two flanges (54a, 54b) projecting from the interior side adapted for engagement with a mounting bracket arrangement including at least two mounting brackets associated with two different roof windows mounted side-by-side, and where the connector element comprises at least one point of attachment adapted for engagement with an engagement section of a flashing member, wherein each side wall is provided with a, preferably elongated, attachment element on an outer side facing away from the gutter, said attachment elements being adapted for engagement with a corresponding attachment element on an extension element or with corresponding attachment members of an adaptor element, characterized by further comprising at least one of: an extension element having two side walls extending substantially in parallel with the side walls of the connector element in a mounted state and forming a gutter extending in continuation of the gutter of the connector element in a mounted state, a first end of the extension element being adapted for engaging the second end of the connector element and a second end of the extension element being adapted for facing away from the connector element, and where the width of the gutter of the extension element at its first end is larger than the width of the connector element at its second end, so that the first end of the extension element may embrace the second end of the connector element in the mounted state, each side wall of the extension element having at its first end on an inner side facing the gutter a corresponding attachment element, which in the mounted state is in engagement with the attachment element on an adjacent side wall of the connector element; and an adaptor element that is provided with at least two corresponding attachment members each adapted for engagement with an attachment member on opposite side walls of the connector element. an extension element having two side walls extending substantially in parallel with the side walls of the connector element in a mounted state and forming a gutter extending in continuation of the gutter of the connector element in a mounted state, a first end of the extension element being adapted for engaging the second end of the connector element and a second end of the extension element being adapted for facing away from the connector element, and where the width of the gutter of the extension element at its first end is larger than the width of the connector element at its second end, so that the first end of the extension element may embrace the second end of the connector element in the mounted state, each side wall of the extension element having at its first end on an inner side facing the gutter a corresponding attachment element, which in the mounted state is in engagement with the attachment element on an adjacent side wall of the connector element; and an adaptor element that is provided with at least two corresponding attachment members each adapted for engagement with an attachment member on opposite side walls of the connector element.