diff --git a/Http/Controllers/CustomersGroupsController.php b/Http/Controllers/CustomersGroupsController.php
index 1404512..3f1c8aa 100644
--- a/Http/Controllers/CustomersGroupsController.php
+++ b/Http/Controllers/CustomersGroupsController.php
@@ -53,6 +53,12 @@ class CustomersGroupsController extends Controller {
 			->pluck('emails')
 			->flatten()
 			->sortBy('email');
+		// Group Emails by their first character.
+		// This is used to display them in collapsible groups.
+		$emails = $emails->mapToGroups(function ($email) {
+			$first_character = substr($email->email, $offset = 0, $length = 1);
+			return [ $first_character => $email ];
+		});
 
 		return view('mmfcustomersgroups::groups/edit', [
 			'mailboxes' => $mailboxes,
diff --git a/Resources/views/groups/partials/edit_form.blade.php b/Resources/views/groups/partials/edit_form.blade.php
index 76cfd69..08284f0 100644
--- a/Resources/views/groups/partials/edit_form.blade.php
+++ b/Resources/views/groups/partials/edit_form.blade.php
@@ -84,27 +84,36 @@
 					</label>
 					<div class="col-sm-6">
 						<div class="multi-container">
-							@foreach ( $emails as $email )
-								<div class="control-group">
-									<div class="controls">
-										<label
-											class="control-label checkbox"
-											for="email-{{ $email->id }}"
-											style="text-align: left;"
-										>
-											<input
-												type="checkbox"
-												name="emails[]"
-												id="email-{{ $email->id }}"
-												value="{{ $email->id }}"
-												@if ( $group->emails()->contains($email) )
-													checked="checked"
-												@endif
-											>
-											{{ $email->email }}
-										</label>
-									</div>
-								</div>
+							@foreach ( $emails as $first_character => $emails_group )
+								<details>
+									<summary
+										style="display: list-item; counter-increment: list-item 0; list-style: disclosure-closed inside; cursor: pointer;"
+									>
+										{{ $first_character }}…
+									</summary>
+									@foreach ( $emails_group as $email )
+										<div class="control-group">
+											<div class="controls">
+												<label
+													class="control-label checkbox"
+													for="email-{{ $email->id }}"
+													style="text-align: left;"
+												>
+													<input
+														type="checkbox"
+														name="emails[]"
+														id="email-{{ $email->id }}"
+														value="{{ $email->id }}"
+														@if ( $group->emails()->contains($email) )
+															checked="checked"
+														@endif
+													>
+													{{ $email->email }}
+												</label>
+											</div>
+										</div>
+									@endforeach
+								</details>
 							@endforeach
 						</div>
 						{{-- @include('partials/field_error', ['field'=>'emails.*']) --}}