This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
隦 combines the mound radical ⻖ with the phonetic component 辟. The exact historical development and original meaning are uncertain.
The left side ⻖ suggests a mound or hill, and the right side 辟 is a complex shape. Without a clear meaning, picture a hidden mound behind a wall of strokes.
For ヘイ, imagine a hay bale sitting on the mound: hay -> ヘイ, and the mound is the left radical ⻖.