To me, and I assume you, 和合の道 is of particular significance in this quote as it relates to 天地人. In other words it appears he is saying:
合気道 = 和合の道 in relation to 天地人
Each is deserving of exploration. I just wanted to emphasize your quote.
You mean separating the two phrases somewhat and relating them indirectly? That might change the nuances a little bit, depending on how you read it. Or do you mean that Aikido is defined specifically in relation to tenchijin?
Anyway, I put the translation as above because Ueshiba refers in other places to things like "the principal of harmonization of heaven, earth and man" (天地人和合の理).