2 neighbors have gates opening up into the utility easement which is within our property lines. Can we restrict access to them?

There probably is no way you can address your concern without making your neighbors angry.  It may be, also, that they have established a right (by virtue of a concept known as adverse possession) to continue using the easement area.  Ordinarily, if a utility company obtains an easement across someone's property, that easement is available for the utility company only.  The property owner still owns the property but the ownership is subject to the utility company's right to use the space and to maintain it for their own purposes.   Now, those rights (the owner's and the utility company's) can be undermined by a neighbor using the easement area -- under a claim of right to do so -- for a long period of time.  that period of time will vary from one state to the next.  If it can be shown, however, that the neighbor's use began by "permission" and not by some "claimed right to do so"), it is likely that even long years' use would not ripen into a legal right.  You should confer with a good real estate lawyer in your area.  Paying a modest conference fee would allow you to learn your specific rights under your state's laws, and what your chances of success might be if you attempt to try and stop it.