Radio Button within Iteration - When user selects radiobutton, store the associated sourceId in attribute 'accountId'

Question

Currently, I'm iterating through a wrapper that includes sourceId (aka accountId) and Opportunity Name, etc. When the user selects a radio button, I want to capture that sourceId in an attribute at the top of my component called "accountId".

    selectAccountRadioGroupOnChange : function(component, event, helper) {
    helper.setAccountId(component, helper);
}

The JS Helper is attempting to get the value attribute on the specific Radio Button that was selected.

    setAccountId : function(component, helper) {
    console.log(component);
    var accountIdOnRadioButton =  component.get("v.selectAccountRadioGroup");    
    component.set('v.accountId', accountIdOnRadioButton); 
    console.log('accountIdOnRadioButton', accountIdOnRadioButton);
}

You can see the console.log returns 'undefined'

<aura:component access="public" implements="force:appHostable,lightning:isUrlAddressable" controller="MyController">    
<!--<aura:attribute name="organizationWrappers" type="List" default=""/>-->
<aura:attribute name="compositeWrapper" type="Object" />  
<aura:attribute name="options" type="List" default="[{'label': '', 'value': 'option1'}]"/>
<aura:attribute name="value" type="String"/>
<aura:attribute name="accountId" type="String"/>

Note I'm trying to set value here to {!organization.sourceId}, which is the Account ID. This would allow me to then get that Account Id later. (Also, note here: onchange="{!c.selectAccountRadioGroupOnChange}")

    <tbody>
        <aura:iteration items="{!v.compositeWrapper.organizations}" var="organization">
            <tr>
                <td scope="row">
                    <lightning:radioGroup name="selectAccountRadioGroup"
                        onchange="{!c.selectAccountRadioGroupOnChange}"
                        variant="label-hidden"
                        options="{!v.options}"
                        value="{!organization.sourceId}"
                        type="radio"
                    />
                    <!--accountId = "{!organization.sourceId}"-->
                </td>
                <td>{!organization.organizationName}</td>                      
                <td>
                    <lightning:formattedDateTime value="{!organization.lastPurchaseDate}"/>
                </td>

Answer 1

component

 <aura:component>
    <aura:attribute name="options1" type="List" default="['1','2','3']"/>
    <aura:attribute name="options" type="List" default="[{'label': '', 'value': 'option1'}]"/>
    <aura:attribute name="value" type="String" default="option1"/>
 <aura:iteration items="{!v.options1}" var="organization">
     <input type="radio" id="{!organization}" name="options"  onclick="{!c.checkboxSelect}"  />
    </aura:iteration>
</aura:component>
}

and in js

checkboxSelect: function(component, event, helper) {
   var selectedaccId= document.querySelector('input[name="options"]:checked').id;
console.log(selectedaccId);


}