EAR MC-3 - Multiple inputs wired up at same time?

I have a number of SUT boxes, and among them I like the sound quality of EAR MC-3 a lot. It has 3 input taps rated for MC coil resistances of: 4 ohms, 12 ohms, and 40 ohms (roughly: 30x, 20x, and 10x step-up ratios, I believe). I have cartridges that are (nearly) ideal for each of these taps, and a dual-arm setup that could use at least 2 of these at a time. The output cable (very low capacitance) runs into a VAC phono stage (in MM mode), and generally stays put that way.

So - rather than swapping the phono input cable when I want to switch arm/cartridge, what are the ramifications (if any) of having both tonearms & carts plugged into 2 different taps at the same time? Will the playing cartridge push current into the other one’s coils (however small)? Are there any risk or performance implications to this arrangement, however slight? I don’t mind swapping the cables in & out too much, but if there’s no problems here then I’ll save the hassle.
Actually, checking out the traf, I see there is no switching. I figured you were talking about crosstalk through the switch. I can't imagine you could connect more than one at a time to the unit.

Yeah, there's no switching mechanism on the MC-3 (or the newer MC-4), so all 3 inputs are direct connections to the primary taps - hence my concern. It's a great sounding versatile SUT; just trying to save some cable swapping if there's no penalty or risk to that. 

Cartridges include Koetsu stones (5 ohms), Shelter Harmony (15 ohms), Benz LPS (38 ohms) - yes I know the Benz is probably better off with a JFET head-amp.