You haven't answered the question why your congregation and/or you would want to be rostered with multiple denominations?
Why not seek Christian unity where and when you can?
You cannot serve two masters. Paul recognized that even married people have to devote time to the spouse that otherwise could be devoted to the Lord. How can a congregation or pastor be adequately devoted to more than one denomination?
I thought that God is to be our master. But you are arguing that it is to be a "denomination"? To the exclusion of other "denominations" and "the Lord"? Huh.
Excellent point! Congregations are not servants of the denomination that they are affiliated with. The denominations are a collection of congregations. The congregations are the church, the denominations are artificial, man-made establishments that are supposed to facilitate the functioning of the congregations, but the denomination is not an authority over the congregations. That's why the only course of discipline available to the denomination regarding a congregation is to sever the affiliation between the denomination and the congregation.
The denomination serves the congregation by providing resources, maintaining a certain degree of good order, facilitating cooperative action to accomplish broader ranges of missions, and other things like maintaining seminaries and a publishing service to make available educational and worship materials. It also handles the training, ordination, and certification of clergy.
If being affiliated with one organization that provides those benefits is good, then being affiliated with two such organizations would surely be better. The only issue would be if the mutually agreed upon standards that define each of two different denominations are at variance with each other to the point of being mutually exclusive.