I assume it is normal that CC3 makes an effort to keep hair fit and conformed when we apply morphs to the head. That is a good thing. However, when I add "elf ears" to the head, the hair distorts badly, and I wonder how to control what affects the hair when it comes to morphs. Example below, where the ponytails and the hair area around the ears get pulled out by the ear morphs. How can I avoid this?

I have noticed that if I convert the hair to an accessory, it stops responding to morphs, but then I cannot apply physics to the ponytails. There must be another way - I hope. Is there a way to keep the hair from responding to specific morphs?

The easiest way to prevent a distortion, is to disable "Conform" for the hair right before you apply the morph. This is not a permanent solution, but is good enough in most cases.

If you need a permanent solution, you would convert hair to Accessory (as you did). But before you convert hair to accessory, send the character to iClone, save hair physics .ini file and weight map(s) (sometimes there is more than one).

Then in CC apply "Transfer Skin Weight" for the hair (selecting "Hair" as a template), send character to iClone, enable physics for the hair and apply saved ini file and weight maps.
Now that hair would always confirm well for the girl with elf ears. You can save the copy of that hair specifically for elf ears.

Side note: I do not know why they have Weight Maps, but not the physics settings in CC. I understand neither can be checked/verified here. But ability to save the settings would save the trip to iClone.
We do not need all those physics sliders, but the simple "Save Settings" button would help a lot while saving and then restoring existing Hair/Cloth physics like in a case above.

There is also the "partial conforming" option, if you ever need it.

Thank you guys for the suggestions. Rigidity groups seem to be the simplest solution, and I didn't know CC could do that. DAZ Studio has that, but it's not as simple to apply as it is in CC. I will give it a try and see how it goes. ^____^