Agreed bart, I'm not sure that the OP has clearly stated his req's or perhaps he doesn't have a clear picture of what his req's are.

I agree with you about the need for anchors, but despite using either /m or /s, I couldn't get things to work with just that. I ended up using \A which worked better, but on its own didn't seem to be enough. I also played with using $, \Z and \z, but I admit I am still a little confused about quite what each does in the contexts of /s and /m. Something I need to play with more.