With over 900 contacts?

Even just my personal CardDAV account has close to 200 contacts.

CardDAV is an extension of vCard. vCard can handle an arbitrary amount of contacts. But who knows, you definitely have more experience in using address book protocols than me.

	▲	dotancohen a day ago \| parent [-]
		I don't claim to know much. But with multiple contact lists and many groups in each list, CardDAV is a must.