hubieran frustrado
-they/you had frustrated
Antecopréterito de subjuntivo para el sujeto ellos/ellas/ustedes del verbo frustrar.

frustrar

Si esos chicos no hubieran frustrado mis planes, me habría largado con todo el oro.
If those kids hadn't thwarted me, I would have made off with all the gold.
Palabra del día
el pavo