Yes, but also no
This is one of those weird cases where it's literally impossible to prevent every single way of doing something.
You can prevent processes like Bitlocker, Truecrypt, and other legitimate encryption programs from accessing the share. Most of the time this is done through Group Policies (Bitlocker comes to mind here) or specific 'all in one' software packages (Look at Kaseya, Labtech, or NAble).
Is it easy?
Lord no. You would have to script a response procedure for each separate encryption program. And, you would have to do so for each new program that comes on the market. It would be time intensive and painful and still only cover maybe 50% of situations. I've scripted with both Labtech and N-Able, and no it is not quick and easy to do.
Wait, you also said no?
That's right, also no. No, because most ransom ware programs aren't using an encryption program. They are just opening specific files in something akin to a text editor and changing the values according to a hash they have generated. You expressly can't stop this type of behavior unless you deny modify access to the share.
So, is it worth it?
Nope. You can probably block legitimate and helpful encryptors, but the dangerous ones are likely to still get through.
A noteworthy edit
While the actual question is handled above, what I believe the intent of the question is can be summed up a little better. Having just had another run in with a nice crypto locker today, I got a refresher for my perspective on the matter.
While we fear crypto lockers as the end all, be all of dangerous infections, sometimes we over estimate them. This particular crypto locker was caught by our enterprise anti virus software in under two minutes. In total it managed to encrypt a total of 7 folders on a network share before being detected and deleted. Strangely, it was actually smart enough to go for the network shares first, a behavior I hadn't seen in previous crypto lockers.
While some very key data could very well have been in the seven folders encrypted (It wasn't in our case), the total effect is still minimal. With a proper backup solution in place, our total recovery time will likely <4 hours and only that high because I am using the opportunity to redeploy the workstation that was infected.
If you are spending more than 4 hours trying to develop a defense against crypto lockers, it probably isn't worth the cost of developing it.