Violagirl the time that you are able to spend with these dogs is invaluable. Thank you for spending your lunchtime with these furbabies, I am sure that they enjoy every minute you give them.
I am really surprised that they only get out of their kennels 2 times a week, does the shelter staff not take them out also? Does the shelter have an area where a couple of dogs can play together for some doggy socializing? Maybe you can take two out at a time and supervise their play.
Maybe you can visit with them in their kennels as well giving them some one on one time that way. Enjoy your time with them
patti