There is a technique to break the power pins of an IC out on an additional unit. In the very long FAQ entry Tutorial: How to make a symbol there is a walk through of creating a multi-unit symbol (6th post on the thread) and the second half of it shows how to create a power-pin only unit on a multi-unit symbol.
In addition to the above FAQ entry, you may want to read these two (in addition to any others you want to read…):
And instead of simply looking through the un-ordered list of FAQ entries, here is the post with the index of FAQ items (including items that aren’t in the FAQ forum area):