First of all, congratulations on starting new businesses!
To answer the question asked, whether you need two EIN's is dependent upon the structure and purpose of your business(es).
However, there are multiple considerations in your question. First, have you set up a company? If you have not set up a company, then I urge you to speak to an attorney. Additionally, are you truly an "employee" (as you suggested), owner, or both. The answer will have different tax ramifications. Finally, if you are merely operating under a trade name, then don't forget to file a DBA with your county clerk.
*This post is meant for general legal and business guidance only. You are strongly urged to obtain the representation of an attorney licensed to practice law in your home state. No post made to this website, no reading of any post, nor any comment you make in regards to any post is protected by attorney/client privilege or constitutes an actual or prospective attorney/client relationship.
It depends. Many companies have multiple lines of business and divisions operating under the same EIN. If you were one of my clients in VA or MA I would want to know how you are organized (Sole Proprietorship, S Corp., C Corp., LLC, Partnership, Business Trust, etc.) and I would want to examine the cross liability exposure of your various lines of business. I would also get your business CPA involved in the conversation.
I suggest you obtain qualified legal counsel in your jurisdiction to assist you with this matter.