Multiple contractors to bid at the same time?

[Hen Ley]

I've heard of people inviting several contractors over at the same time to provide estimates.  Is this considered acceptable or does it make it too awkward for everyone?   I live in a small town and so there might be many familiar faces to one another, but it seems efficient!  And I also don't want it to appear that I'm intentionally forcing them to bid against one another...