= List.Accumulate(Text.ToList("AAbb123BBcc234") & {"A"}, {{},"","",0,""},(x,y)=>
if x{4}="" then
{x{0},x{1},y,x{3},y}
else if x{4} =y then
{x{0},x{1},x{2}&y,x{3},y}
else if y < "A" then
{x{0},x{1},x{2},x{3}+Number.From(y),y}
else if x{3} = 0 then
{x{0},x{1}&x{2},y,x{3},y}
else
{x{0}&{{x{1},x{2},x{3}}},"",y,0,y}
){0}