When seeking synonyms for the phrase "be allied to," it can be helpful to consider the context of the sentence. Consider using the word "connected" or "associated" to express the same idea. "Aligned with" or "bound by a common interest" can also be a suitable alternative. Another option may be to use "in partnership with" or "united with" to convey the same concept. In some cases, "allied with" or "connected with" may be more appropriate depending on the exact context of the sentence. Ultimately, choosing the best synonym for "be allied to" is dependent on the specific phrasing and context of the sentence being used.