Ability grouping is a common practice in elementary mathematics instruction, but some research suggests that grouping by ability can exacerbate existing inequities, and there is evidence that alternatives to grouping can improve learning experiences for all students. In this paper, we describe an effort to support teachers in using equitable teaching practices that was part of an Elementary Mathematics Specialist (EMS) certification program at a public university in the United States. We employ multiple perspectives in our collaborative action research approach: the first author was the director of the EMS program, the second author was a graduate researcher working to support the program, and the third, fourth, fifth, and sixth authors were all teachers in the program. We start by introducing efforts to address equity from the perspective of program designers, including specific activities used during a Summer Institute to prompt consideration of alternatives to ability grouping. Then we share several experiences of reducing ability grouping from the perspectives of four teachers who were participants in the program, noting successes and challenges. We conclude with implications for research and practice.