Suggestion (Sp): A bard of 6th level or higher can use his performance to make a suggestion (as per the spell) to a creature he has already fascinated (see above). Using this ability does not disrupt the fascinate effect, but it does require a standard action to activate (in addition to the free action to continue the fascinate effect). A bard can use this ability more than once against an individual creature during an individual performance.
Making a suggestion does not count against a bard's daily use of bardic performance. A Will saving throw (DC 10 + 1/2 the bard's level + the bard's Cha modifier) negates the effect. This ability affects only a single creature. Suggestion is an enchantment (compulsion), mind affecting, language-dependent ability and relies on audible components.
So, if a bard of 7th level has 3 targets fascinated with his performance, he can use the Suggestion (Sp) ability on each of them as a standard action, doing one each round. And it says "use his performance to make a suggestion (as per the spell)"
[url=http://paizo.com/pathfinderRPG/prd/spells/suggestion.html#_suggestion][/url]
So each of these Suggestions lasts for Duration 1 hour/level or until completed? And not just until the Bardic Performance is over?
If the Suggestions ended when the performance ended, the ability would be utterly worthless. Not just the limited rounds/day aspect, but also that they'd have to remain hearing your performance.
It's as the spell. Once you give the suggestion, you can cease performing and the spell effect will persist for hour/level or until completed. So, just do your performance beforehand in a secluded area, then unleash your sleeper cell agents to do your bidding! :)