frequency divider for two output frequencies
Yes. Though it is probably a little easier to make a fixed /5 divider, and then one that's selectable /6 or /7.

Do you really want to make it from flip flops? Perhaps for the exercise, or you only have a box of HC74s? Because you can't make it purely from flip flops, you will need a few extra gates to make them recycle at 5, 6 or 7 counts.

It's somewhat easier to make a divider from a loadable counter like an HC163 or an HC161, which is basically 4 flip flops in a package, with a sprinkling of gates around them that make them more useful.

For how to make a /5 or /7 counter from flip flops, looks up the schematic diagram of an HC161, and see how the extra gates are arranged.