@RogerCooper I think you can do this without even having to use a new unit, you can make a supportAttachment that gives infantry -1 strength, then attach it to the infantry itself and have it only apply to Russians. Something like
<attachment name='supportAttachmentRussiansInfantryEquipmentShortage' attachTo='infantry' javaClass='UnitSupportAttachment' type='unitType'>
<option name='unitType' value='infantry'/>
<option name='faction' value='allied'/>
<option name='side' value='offence'/>
<option name='dice' value='strength'/>
<option name='bonus' value='-1'/>
<option name='number' value='1'/>
<option name='bonusType' value='EquipmentShortage'/>
<option name='players' value='Russians'/>
</attachment>