Can efile 2 returns separately one with a company and the other one with a different company?

Not for the same person.

You only file one time... all W2's are filed on the same tax return.

You can only file ONE Federal income tax return and ONE state income tax return per state. NONE of the taxing authorities cares how, or even if, you file with any other taxing authority.

No. You can only file one return.

This makes no sense. What are you really asking?

If you received more than one w-2, you file them on the same return.

If you are talking federal and state, the software for state needs the federal info...which means, usually, the same company.