Star Crossed Lovers (Enemies to Lovers)

Enemies to lovers, but not necessarily in the sense that the leads hate each other in the beginning. More of a Romeo and Juliet situation. A pair that seems to be "thwarted by a malign star" and therefore doomed / impossible from the start.

The leads (knowingly or unknowingly) belong to rival groups (rival families, factions, tribes, nations, etc.) but end up overcoming the odds to become lovers anyway. The rivalry is bigger than the two individuals (i.e., it's not just rooted in their personal grudges or feelings). In some cases the leads might not even have any personal ill will towards each other. 

Each lead has someone from their "group" that sees an enemy or a threat when they look at the other lead.