Putting together a quartet

I recently released an album of my music, which was recorded with string players I've never met via the Internet. The album has been quite well received, and I've been asked a few times to do it live. So, it seems I need to put together a string quartet, with myself on piano and some local musicians. For the kind of music I write (vaguely minimalist or so-called post-classical) it's pretty common for a composer to have their own ensemble (ie Philip Glass Ensemble, Michael Nyman Band, Max Richter Ensemble, etc.).

The problem is that I'm not at all familiar with the practicalities of it. Am I expected to pay all of the musicians for every rehearsal & performance at union rates ? That would get far too expensive for me, but likewise I realise that the musicians need to get something out of it. I would use them on my next album, and pay them normal rates, so that would be beneficial to them - but the live side is a mystery to me.

Has anyone here put together an ensemble, with strangers rather than friends (which is completely different) ??