First of all, you may be in violation of your own lease if you are subleasing. Many leases prohibit subleasing and/or prohibit subleasing without the consent of the landlord. That being said, are your subleases written or oral? If you have a written lease with your subtenants, absent a breach or a failure to pay rent, you cannot unilaterally terminate the lease for no reason. If you don't have written leases and your subtenants are periodic tenants, then you can provide written notice to terminate the tenancy (in most states to terminate a month to month to month tenancy, you need a minimum of 30 days).
DISCLAIMER: Brandy A. Peeples is licensed to practice law in the State of Maryland. This answer is being provided for informational purposes only and the laws of your jurisdiction may differ. This answer based on general legal principles and is not intended for the purpose of providing specific legal advice or opinions. Under no circumstances does this answer constitute the establishment of an attorney-client relationship. For legal advice relating to your specific situation, I strongly urge you to consult with an attorney in your area. NO COMMUNICATIONS WITH ME ARE TO BE CONSTRUED AS ARISING FROM AN ATTORNEY-CLIENT RELATIONSHIP AND NO ATTORNEY-CLIENT RELATIONSHIP WILL BE ESTABLISHED WITH ME UNLESS I HAVE EXPRESSLY AGREED TO UNDERTAKE YOUR REPRESENTATION, WHICH INCLUDES THE EXECUTION OF A WRITTEN AGREEMENT OF RETAINER.