Table.Split by a delimeter

I suggest

•  Add an Index Column (zero-based)
• Use List.PositionOf to obtain the position of all the nulls, as well as the number of rows in the table
• Use List.Generate to generate the individual tables by using Table.SelectRows relative to the Index column
• Remove the Index column within the List.Generate function

...
    #"Added Index" = Table.AddIndexColumn(#"Previous Step", "Index", 0, 1, Int64.Type),

    n = List.PositionOf(#"Added Index"[Name],null,Occurrence.All) & {Table.RowCount(#"Added Index")},

    #"Split Table" = List.Generate(
        ()=>[t=Table.SelectRows(#"Added Index", (tb)=> tb[Index]<n{0}), idx=0],
        each [idx] < List.Count(n),
        each [t=Table.SelectRows(#"Added Index", (tb)=>tb[Index] > n{[idx]} and tb[Index] < n{[idx]+1}), idx=[idx]+1],
        each Table.RemoveColumns([t],"Index"))
in
    #"Split Table"

If, as you imply in your question, you only want the FIRST split, then just use:

Table.Split(#"Previous Step", List.PositionOf(#"Previous Step"[Name], null, Occurrence.First)){0}