Which takes precedence: inviting non-Muslims to Islam, or maintaining kinship ties?

It is best to combine dawah (preaching Islam) with maintaining ties of kinship, for both are religious obligations. The Prophet, peace and blessings be upon him, and his companions combined them. If time is limited and dawah is a communal obligation (fard kifayah), then preachers should coordinate so that some can dedicate themselves to maintaining ties of kinship. However, if there is no one else to perform dawah, then dawah takes precedence, as it falls under the general category of jihad, which is among the best of deeds.