Back on topic, I tank with Ifrit blade (p5 just keeps ending in tragedy before my eyes) for relic + 1 speed runs, and I find I *usually* can hold agro with:

shield lob
fast blade -> 1
circle of scorn (repeat on CD)
savage blade -> 1
spirits within (repeat on CD)
flash
rage of halone -> 1
fast blade -> 1
savage blade -> 2
rage of halone -> 3
flash
fast blade -> 1
savage blade -> 3
rage of halone -> 2

Last run I had the exact scenario you describe, lancer in full ilvl 90 + relic +1 refusing to AOE and a slightly less geared bard doing nothing but AOE. I lost agro on 2 mobs in the run.

It's hard and it's frustrating, but try and just take those runs as opportunities to get even better at tanking. They'll make your other runs feel really really easy. :P