not sure what you mean by ValidationGroup of the web part.
<%@ Control Language="C#" AutoEventWireup="true" Inherits="TheScene.Web.WebParts.RegisterBands" Codebehind="MembershipEditor.ascx.cs" %>
<%@ Register TagPrefix="MonoX" TagName="StyledButton" Src="/MonoX/controls/StyledButton.ascx" %>
<%@ Import Namespace="MonoSoftware.MonoX.Resources"%>
<div class="membership-module-container input-form" style="">
<div id="Div1" runat="server">
<asp:ValidationSummary ID="validationSummary" CssClass="validation-summary" runat="server" />
<asp:Label ID="ErrorMsg" runat="server" ForeColor="Red"></asp:Label>
</div>
<div class="register">
<h2>
<%= Page.User.Identity.IsAuthenticated ? DefaultResources.MembershipEditor_Title_UpdateAccount : DefaultResources.MembershipEditor_Title_CreateAccount %>
</h2>
<dl>
<dd>
<asp:Label ID="lblUserName" runat="server"></asp:Label>
<asp:Label ID="lblUrlBandName" runat="server" Text="UrlBand"
meta:resourcekey="BandUrl"></asp:Label>
<asp:TextBox ID="txtUserName" runat="server"></asp:TextBox>
</dd>
<dd>
<asp:Label ID="lblBandName" runat="server" Text="BandName"
meta:resourcekey="BandName"></asp:Label>
<asp:TextBox ID="txtBandName" runat="server"></asp:TextBox>
<asp:RequiredFieldValidator ID="vldRequiredUserName" runat="server"
ControlToValidate="txtUserName" Text="!" SetFocusOnError="true"
CssClass="validator ValidatorAdapter" Display="Dynamic"
EnableClientScript="False" Enabled="False" />
<asp:CustomValidator ID="vldCustomUserName" runat="server"
ControlToValidate="txtUserName" ErrorMessage="Invalid Band Name" Text="!" SetFocusOnError="true"
CssClass="validator ValidatorAdapter" Display="Dynamic" Enabled="False" />
<asp:CustomValidator ID="vldBandName" runat="server"
ControlToValidate="txtUserName" OnServerValidate="BandNameValidate"
ErrorMessage="Invalid Band Name" Text="!" SetFocusOnError="true"
CssClass="validator ValidatorAdapter" Display="Dynamic" />
</dd>
<dd>
<asp:Label ID="lblGenre" runat="server" Text="Genre" meta:resourcekey="Genre"></asp:Label>
<asp:DropDownList ID="DropGenre" runat="server"></asp:DropDownList>
</dd>
<dd>
<asp:Label ID="lblFaceBook" runat="server" Text="FaceBook"
meta:resourcekey="FaceBook"></asp:Label>
<asp:Textbox ID="txtFaceBook" runat="server"></asp:Textbox>
</dd>
<dd>
<asp:Label ID="lblTwitter" runat="server" Text="Twitter"
meta:resourcekey="Twitter"></asp:Label>
<asp:Textbox ID="txtTwitter" runat="server"></asp:Textbox>
</dd>
<dd>
<label for="<%= txtPassword.ClientID %>"><%= DefaultResources.MembershipEditor_Password %></label>
<asp:TextBox ID="txtPassword" runat="server" TextMode="Password"></asp:TextBox>
<asp:RequiredFieldValidator ID="vldRequiredPassword" runat="server" ControlToValidate="txtPassword" Text="!" SetFocusOnError="true" CssClass="validator ValidatorAdapter" Display="Dynamic" />
</dd>
<dd>
<label for="<%= txtRepeatPassword.ClientID %>"><%= DefaultResources.MembershipEditor_RepeatPassword %></label>
<asp:TextBox ID="txtRepeatPassword" runat="server" TextMode="Password"></asp:TextBox>
<asp:RequiredFieldValidator ID="vldRequiredRepeatPassword" runat="server" ControlToValidate="txtRepeatPassword" Text="!" SetFocusOnError="true" CssClass="validator ValidatorAdapter" Display="Dynamic" />
<asp:CompareValidator ID="vldCompareRepeatPassword" runat="server" ControlToValidate="txtRepeatPassword" Text="!" SetFocusOnError="true" ControlToCompare="txtPassword" Operator="Equal" CssClass="validator ValidatorAdapter" Display="Dynamic"></asp:CompareValidator>
</dd>
<dd>
<label for="<%= txtEmail.ClientID %>"><%= DefaultResources.MembershipEditor_Email %></label>
<asp:TextBox ID="txtEmail" runat="server"></asp:TextBox>
<asp:RequiredFieldValidator ID="vldRequiredEmail" runat="server" ControlToValidate="txtEmail" Text="!" SetFocusOnError="true" CssClass="validator ValidatorAdapter" Display="Dynamic" />
<asp:RegularExpressionValidator ID="vldRegexEmail" runat="server" ControlToValidate="txtEmail" Text="!" SetFocusOnError="true" CssClass="validator ValidatorAdapter" Display="Dynamic" />
</dd>
<asp:PlaceHolder ID="plhRememberMe" runat="server">
<dd>
<label> </label>
<asp:CheckBox ID="chkRememberMe" runat="server" style="float: left;" />
<label style="margin-top: 2px; float: left;" for="<%= chkRememberMe.ClientID %>"><%= DefaultResources.MembershipEditor_RememberMe %></label>
</dd>
</asp:PlaceHolder>
<dd>
<asp:Label ID="labInfo" runat="server"></asp:Label>
</dd>
</dl>
<div class="input-form">
<div class="button-holder" style="float: right;">
<MonoX:StyledButton ID="btnCreateAccount" runat="server" CssClass="CssFormButton"></MonoX:StyledButton>
<MonoX:StyledButton ID="btnUpdateAccount" runat="server" CssClass="CssFormButton"></MonoX:StyledButton>
</div>
</div>
</div>
</div>