What design pattern can be used for feature toggle spaghetti?

The company that I work for has gone off the deep end with feature toggles-configuration keys that turn on/off particular behavior based on certain conditions. Martin Fowler actually refers to them as business toggles (http://ift.tt/18DVASs).

We have many clients all using the same service, but each wants slightly different behavior. Even worse, many want certain subgroups of their users to see different behavior. Thus, we use business toggles. The toggles have become a spaghetti ball of if/else logic that with occasionally unexpected interactions.

Are there any design patterns useful in managing a situation such as this?

Cheers!