Realistic Woodwind and String parts (true legato)

With regard to making midi sound real, one of the things I have been trying to get to is the ability to differentiate between (for instance) a flute moving from one note to the next by maintaining breath and changing fingering (legato) as opposed to tonguing from one note to the next, or the difference between a violin changing fingering during the same bow stroke as opposed to using a fresh bow stroke.
 
Notes played on the keyboard have basically the same attack.  Is there a function in Sonar to remove the attack on notes? Years ago I used to do this in Pro Audio 9 using a CAL to basically take a whole note and change the pitch to turn it into a group of notes played legato.  I can't find that CAL anymore and I don't even know if it would work in Platinum.

I read this with interest and thought I would throw another thought into the mix. Before I do though, I want to qualify that I'm aware you probably aready know most of this. I am coming from a basic level for those who are just starting.
 
Midi never makes a sound...so to say I need to know how to make midi sound good is only part of the picture. I think I know what you mean't by that...but I'm simply clarifying...the other half of the picture is sound library quality and included articulations. I can have the best midi in the world, but if my samples aren't very good or I don't have recorded articulations to play all I can do is attempt to emulate some kind of a fix in midi programming, and it can be done to a fairly acceptable level, but I would always want good included articulations, high quality samples and maybe round robin capability. I might also try to augment with real strings if at all possible....lots of decent players in community orchestras who might help you out for a few bucks! 
 
Hollywood strings, Albion...Orchestra Runs...Kirk Hunter...check these out, but be ready to pay for good samples. Some of these programs come pre panned and ready to go.

Jerrylan9638
 
Notes played on the keyboard have basically the same attack.  Is there a function in Sonar to remove the attack on notes?

You're too late - it's closing the barn door after the horses have left. 
 
You don't say what sound source the MIDI is driving.  For synths, patches can do things with legato mode to maintain existing envelope positioning when changing to a new note.  For samplers, good (read expensive) libraries will articulations to control attack, among other things. 
 
In theory, one could do some stuff with pitch bend to continue a line of notes in a legato fashion - but, man, what a headache to program it!  And it would likely sound fake much of the time in any case.