RelatedListDemo.page

<apex:page controller="RelatedListDemoController">
    <apex:repeat value="{!accounts}" var ="item">
    	<apex:relatedList list="Contacts" subject="{!item.Id}" />
    </apex:repeat>
</apex:page>

RelatedListDemoController.cls

public class RelatedListDemoController{
    
    public List<Account> accounts {get; set;}
    
    public RelatedListDemoController() {
        this.accounts = [SELECT Id FROM Account ORDER BY Name ASC LIMIT 5];
    }
}