public ICollection<Asset> AddForcedAssets(ICollection<Asset> assets) { // Add URLs with Force == true. foreach (Asset url in Assets) if ((Force || url.Force) && !assets.Contains(url)) assets.Add(url); // Get all URL groups. ICollection<string> groups = AssetsHelper.GetGroups(assets); // Add all URLs from specifiс groups. foreach (Asset asset in Assets) { if (groups.Contains(asset.Group) && !assets.Contains(asset)) assets.Add(asset); } return assets; }