PQ - restart numbering

src		src	Index
a		a	1
a		a	2
a		a	3
b		b	1
b		b	2
B		B	1
B		B	2
c		c	1
d		d	1
d		d	2
e		e	1
e		e	2
E		e	3
E		e	4
E		e	5
E		e	6
E		e	7
E		E	1
E		E	2
E		E	3
e		E	4
e		E	5
e		E	6
e		E	7
e		E	8

Code:

---

// Table1
let
    Source = Excel.CurrentWorkbook(){[Name="Table1"]}[Content],
    Grp = Table.Group(Source, {"src"}, {{"Index", each Table.AddIndexColumn(_,"Index", 1, 1)[Index], type list}}),
    Exp = Table.ExpandListColumn(Grp, "Index")
in
    Exp

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