Absolutely! Just make sure that the Plan documents for the Retirement Plans of each company (yours, the acquiring company, and any other company closely related enough to count) spell out who exactly is covered under their separate Plans.

To be sure that your Plan remains separate from the acquiring company (if that is what you want), I would advise you to get someone to either represent you in the details, or at least advise you on your options and the best way to handle/word them. This could be an attorney with specialization in Retirement Plans or even someone designated as knowing a great deal about Employer-Sponsored Retirement Plans (such as a person with the ERPA or similar designation).

Just be sure to address this issue early on in the acquisition/merger process. Sorting out Retirement Plan details are not always quick to happen!