If you want a randomized gate, a logic module would be nice. An accent might come in the form of a random gate rather than a variable voltage.
The Q-Bit NanoRand seems to have a random gate output you can clock to the gate feeding your ostinato. Patch that gate to a separate envelope generator and then that EG to something like your filter cutoff. Now you quickly sweep the filter as your accent.
The other way involves using a logic module... if your S&H doesn't do random gates. I'll lay that out here for anyone else reading:
You can use your Q-Bit NanoRand to generate a random sample and hold signal. Trigger the S&H with the same gate feeding your envelope generator (assuming you're using an EG for amplitude envelope). Then feed that same gate to one input of your logic module and the S&H output to the other logic input.
The S&H module will spit out a gate only when your original gate is present through the logic gate's "AND" output... when the S&H circuit spits out a voltage that is high enough to register as "TRUE".
You can modify the amount of accents by inserting an attenuverter with an offset... like the Befaco Dual Attenuverter. Offsetting the S&H output higher will increase the likelihood of a gate... setting it lower will reduce the chance of a gate.