using System;
using System.Linq;
using System.Text.RegularExpressions;

public class Test
{
	public static void Main()
	{
		var p = new[] {
			@"aaa[0-9]{2}\.zip",
			@"bbb[0-9]{2}\.zip"
		};
		var pat = new Regex($"({string.Join(")|(", p)})");
		var match = pat.Match("We have bbb12.zip match");
		//var grps = match.Groups.Cast<Group>();
		for (var n=1; n <= p.Count(); n++)
		{
			if (match.Groups[n].Success) 
			{
				Console.Write("{0} group matched, the pattern is {1}", n, p[n-1]);
				break;
			}
		}
	}
}