Legal remedies for unauthorized commercial use of shared property

If it is an undivided joint property then the other party need to have obtained NOC or consent from the other party.

The aggrieved party can approach court for injunction against this illegal act

Since property is joint so both the parties have right to use and enjoy it so better gole suit for partition of property and injunction to get restrain him such activity.

Yes, the aggrieved party  has option to initiate a civil action against other. However, an amicable settlement would be the best option. The adalats functioning under the Legal Services Authority could be approached in the first instance.

A suit has already been filed by a third family member, who is neither part of Party 1 nor Party 2 but shares the same land. The case is currently pending in court. Despite this, Party 2 has commenced their business operations on the shared property without awaiting the court's decision. Additionally, Party 2 has constructed an ~8-foot-wide road on the common land leading to their home.

I am afraid, you are trying to mislead this forum without disclosing the material facts. Your posting and subsequent clarifications constitute a riddle than a query.

If the party to the suit is indulging in the activities involving the suit property then the aggrieved person can file an injunction application to restrain him from indulging in such activities which will adversely affect the conduct of the suit.

You may consult your avocate and take decision accordingly 

I apologize, sir. My response, along with the query, now presents the complete scenario. There are no additional hidden details.

You can proceed as suggested here by experts or you can discuss with your advocate and proceed as advised by your advocate