Anti-discrimination laws make freedom of association illegal. But most of the freedom of association you want, you can have by judicious use of signaling and incentives.
Any organization which is not explicitly right-wing (including a business) will sooner or later become explicitly left-wing (Conquest's Second Law.)
Diversity is our core value.
This is mainly because leftism has established itself as the default, the prevailing Zeitgeist, the dominant narrative. So if you're in business, mouthing leftists platitudes is the path of least resistance and the way to alienate the fewest potential customers or employees. Who could disagree with the universal values of tolerance, diversity and equality? If there is such a troglydyte running around, you can pick up signaling points by repudiating him and/or his business.
Except recent cases like Chic-Fil-A, Hobby Lobby, Barilla, and others, show that there are vigorous niches to be filled serving non-leftists.
And these niches can be grown relative to the leftist substrate because they can be normatively productive and non-parasitic. But the leftosphere is obliged, not only to tolerate, but actually to celebrate, a whole spectrum of blatantly parasitic, rent-seeking, individuals and behaviors.
The first step to shirking this tax is signaling. Just do and say things that will send the jimmies of those you wish to exclude through the stratosphere. You shouldn't be hard pressed to think of examples. Pick things that will either leave your target market nonplussed, or actually get you congratulatory high fives.
You can bolster the effectiveness of your signaling by layering on incentives. The basic idea is to bundle two or more things that your target market will consider goods (and therefore worth paying for) but at least one of which those you don't wish to deal with will consider bads.
Charitable or political contributions are great here because increasing the price of your offerings (whatever they may be) tends to exclude undesirable elements automatically, and choosing your contributions wisely will enhance your appeal to the right sort of clientele. They were going to make charitable and political contributions anyway. So making these part of the deal is an extremely high quality form of signaling and a way to really zero in on a particular subset of the market.
In addition to political orientation, it's more than OK to leverage the power of ethnocentrism.
So called "middleman ethnicities" are able to dominate certain trades, professions, and lines of business in certain countries, mainly by leveraging high ingroup trust and low transaction costs to practically insulate themselves from competition. Well, no one is higher trust than white people. And we have other abilities and talents, which, if not exactly unique, we exhibit to unique extents. And white altruism meshes well with the use of charitable and political contributions as signaling.
So here's wishing everyone safe and successful signaling. And I look forward to hearing (and seeing) how you flesh out these ideas further.