Sandhills is not a standard Jain term. You might be mixing up two related Jain concepts:

• Śvetāmbara (श्वेतांबर): literally “white-clothed.” This is the sect whose monks and nuns traditionally wear white robes, in contrast to the Digambaras who practice without clothes. The term and meaning are well established in Jain texts and tradition. If you meant the sect by “Shwetambar,” it refers to white-clothed Jain monks/nuns and their followers.

• Sandhyā (संध्या): a term meaning twilight or evening prayers. In Jain practice, both Śvetāmbara and Digambara traditions have prescribed times for daily prayers and rituals, including evening observances, but this is a separate concept from the sect name.

If you were thinking of a different word that sounds like “sandhills,” please share a bit more context (where you saw it, the sentence it appeared in), and I’ll give you a precise Jain-era meaning.