Three wires under a single lug is a separate issue from whether or not each machine requires its own disconnect.
If all three machines are allowed on the same disconnect then you still have to find a way to properly terminate them. Which it will be similar to how you connect them if you have three disconnects supplied by same feeder. Except the splicing will be on line side instead of load side of disconnect(s).
Without any more information we have to assume the machine is to be installed to art 422 - appliances. If it is electric space heating, air conditioning, or a motor there are other articles that apply but requirements are similar in most of those articles also.
If appliance is permitted to be cord and plug connected, then the cord and plug qualifies as a disconnecting means.
If the appliance has a unit switch with a marked off position - it may qualify as a disconnecting means.
If the appliance is less than 300VA or 1/8 hp the branch circuit overcurrent device is permitted to be the disconnecting means - even if not within sight. Note: it does not say if the circuit is permitted to supply other loads.
Some of these items need consideration before a definite answer can be given.
