Shell Programming and Scripting

I have the file like this:

Timestamp URL Text 1331635241000 http://example.com Peoples footage at www.test.com,http://example4.com 1331635231000 http://example1.net crack the nuts http://example6.com 1331635280000 http://example2.net Loving thisEach column is tab separated. I need to extract only the URLs from column 2 and column 3 if in case of the no URLs then leave it empty for example to get the result like this:

URL Text http://example.com www.test.com,http://example4.com http://example1.net http://example6.com http://example2.net

I tried this script

Code:

awk 'BEGIN {FS="\t"} {print $2,$3}' file | grep -oP '(((http|https|ftp|gopher)|mailto)[.:][^ >"\t]*|www\.[-a-z0-9.]+)[^ .,;\t>">\):]'

This script can give me the all URLS in a single column without the header. Any suggestion to resolve this.