You can do it yourself to be honest and find people who can trek with you and your group. If you want i can try and ask some locals to help closer to August.
I think bro if you wanna go you should do it in July otherwise in aug it is also great and you should like plan yourself to avoid extra commission charges
You can trek in Dzouku valley which is located in Nagaland . "Finderbridge" is one company which organises trip to Dzouku valley you can visit their page here in tripoto and Instagram too. the best time to visit is June July and December
23 may is the best time to trek because many traveller start trreking on that day bcz hemkund sahib darshan is also open on 23 may and yo will get free accomdation and food too....