TVBLS

I'd like to simulate an electret microphone in a summing amplifier circuit. The electret mics I'm using have an output impedance of 2.2Kohm. When a use an AC source component to simulate a mic signal I can set the amplitude and frequency of the source, but I don't see a way to set the impedance of an AC source, similar to how LTSpice has a source resistance parameter. Is there a way in Multisim live other than placing a resistor in series with the AC source output? Thanks.