Should there be monthly 2-3 sessions from seniors to newly joined juniors for day to day work, apart from general training?

..............yes agree  and good

it certainly can help to build strong work and professional relation among workers, but it also can waste the precious time of senior employees. 

What I prefer is, assign newly hired employees to a schedule, where they work side by side with a senior employee for a week, so they can learn different tasks, and gain more experience on one to one type of session instead of a group or a long meeting. 

Thanks 

Yes, it is a good manner for informal training and integrating 

Thank you for the invitation

this is a good ideas  

Thank you for invitation. I agree with experts answer & I  am looking forward more experts answer.

Thank you for the invitation

Yes I agree   

With greetings and appreciation

It will normally depend on the background of the junior and availability of time of the senior.  It could be daily 1 or 2 hour session for a week and thereafter one 2 hour session for the next 3 weeks or so. 

Interaction within the organization among the high-ups and junior executives help to understand organization and business in well manners as well as it create soft communication channels for better understanding.

Thanks for invitation,

Agree with the idea, taking into consideration that most institutions are invited their new staff for introductory training programs, in order to be familiar with the institute's activities before they are starting their actual job.