You could if you wanted to have a lamb and veg pasta sauce.

Well here is a made up recipe you could do using your ingredients. I would cook the veg alone because your meat is already cooked and then add that in maybe when there's an hour to go.

1 can tinned tomatoes, crushed
3/4 tsp dried organo
1/2 tsp dried basil
1 bay leaf (optional)
1-2 cloves garlic crushed
1 1/2 tsp sugar
salt and pepper
1 onion chopped
2 cups chopped mixed vegetables

Cook on high for 3-3 1/2 hours. Keep an eye on it, if it gets too thick add some stock or plain water, or even some more tomatoes. If it's too thin, thicken with cornflour at the end. Put your lamb in after 2 hours.

I think that will be ok.