Hello There,
Thanks for writing in! Regretfully this isn’t a feature offered by X. It could be possible with custom development, but this would be outside the scope of support we can offer. You may wish to consult a developer to assist you with this. X is quite extensible with child themes, so there are plenty of possibilities. Thanks for understanding. Take care!
This link might help:http://stackoverflow.com/questions/5902822/stopping-fixed-position-scrolling-at-a-certain-point. That script will help for the scrolling.
Always,
X