It is not possible to bind same gridview with multiple tables.
For this purpose, DataRepeater is best idea.
<asp:Repeater ID="Repeater1" runat="server">
<HeaderTemplate>
Your Header
</HeaderTemplate>
<ItemTemplate>
<asp:GridView runat="server" ID="grd" AutoGenerateColumns="false">
<Columns>
</Columns>
</asp:GridView>
</ItemTemplate>
</asp:Repeater>
Use Bootstrap Accodion for Collapse and expand in ItemTemplate and put the Grid in Accordion.
In Repeater data bound event, find the grid control using FindControl method and bind the data to grid view.
GridView grid = e.Item.FindControl("grd") as GridView;
grid.DataSource = dataTable;
grid.DataBind();