In the new (as yet unreleased) version:
Intercept: Can be set on any target, only draws fighters/frigates by default (but can have other ships direct-assigned to it), results in single-minded dedication to attacking the target. To a point, anyway - it won't be actively suicidal, but it'll attempt to attack that target if possible.
Engage: Can be set on any target larger than a frigate, draws all kinds of ships, not single-minded (will engage nearby targets of opportunity).
Bombers assigned to either will go for the specified target, w/o being distracted by nearby enemy ships.