Something as described in this tutorial?
In short: multi unit symbol with an extra unit for power pins. (Has drawbacks in the current library file format that will be fixed in future versions. We hoped it will be included in v5 but this seems very unlikely at the moment. Most likely in v6 or in the worst case even later.)
We library maintainers see this as the best option with the current symbol library format. In fact, new symbols are not accepted with hidden power pins. (Sadly nobody volunteered to fix the current 74xx lib. Are you prepared to do it?)