Background: Supporting students during collaborative learning in mathematics is challenging for teachers. We developed the Small-Group Scaffolding Tool (SGS-Tool) to assist teachers regarding how and when to offer support. The tool is based on three characteristics of scaffolding small groups at the group level: contingency to the "group," phasing out content support when the group can continue independently, and transferring responsibility for learning to the "group." Method: We investigated whether the scaffolding behavior of teachers using the SGS-Tool was more adapted to the group level than that of teachers not using the tool. Participants were four teachers and their seventh grade classes. The topic was Early Algebra. We analyzed teachers' scaffolding behavior with one group during five lessons. Findings: The SGS-Tool offered teachers support when the groups discussed mathematics, but adaptations of the tool are needed. Overall, the SGS-Tool seems to be a promising tool for supporting mathematics teachers in scaffolding groups at the group level. Contribution: Our study provides insight into what scaffolding small groups at the group level entails and how teachers can apply it.