<style>
    .k-group-footer + .k-group-footer {
       display:none;
    }
</style>

Group by the Vacation and Team columns to see the effect

<TelerikGrid Data=@GridData Groupable="true" Pageable="true">
    <GridColumns>
        <GridColumn Field=@nameof(Employee.Name) Groupable="false" />
        <GridColumn Field=@nameof(Employee.Team) Title="Team">
            <GroupFooterTemplate>
                Team group footer
            </GroupFooterTemplate>
        </GridColumn>
        <GridColumn Field=@nameof(Employee.IsOnLeave) Title="On Vacation">
            <GroupFooterTemplate>
                IsOnLeave group footer
            </GroupFooterTemplate>
            </GridColumn>
    </GridColumns>
</TelerikGrid>

@code {
    public List<Employee> GridData { get; set; }

    protected override void OnInitialized()
    {
        GridData = new List<Employee>();
        var rand = new Random();
        for (int i = 0; i < 15; i++)
        {
            GridData.Add(new Employee()
            {
                EmployeeId = i,
                Name = "Employee " + i.ToString(),
                Team = "Team " + i % 3,
                IsOnLeave = i % 2 == 0
            });
        }
    }

    public class Employee
    {
        public int EmployeeId { get; set; }
        public string Name { get; set; }
        public string Team { get; set; }
        public bool IsOnLeave { get; set; }
    }
}