Demo code using InGroupsOf from Umbraco.Core.EnumerableExtensions

gistfile1.cs

@using Umbraco.Core
@using uComponents.DataTypes.UrlPicker.Dto
@{
    //var items = Model.resourceLinks.Items as List<UrlPickerState>;
    var items = new List<UrlPickerState>
    {
        new UrlPickerState { Title = "Link1" },
        new UrlPickerState { Title = "Link2" },
        new UrlPickerState { Title = "Link3" },
        new UrlPickerState { Title = "Link4" },
        new UrlPickerState { Title = "Link5" },
        new UrlPickerState { Title = "Link6" },
        new UrlPickerState { Title = "Link7" },
        new UrlPickerState { Title = "Link8" }
    };
    
    foreach (var group in items.InGroupsOf(4))
    {
        <h4>Links</h4>
        <ul>
        @foreach (var links in group)
        {
            <li>@links.Title</li>
        }
        </ul>
    }
}