Integration Framework - HTTA - detained request´s in queue

Hello,
I have scenario where I send JSON via HTTA adapter.
When from recipient does not come 'Success 200 OK', so according the error handling it will repeat again.
But I suspect, that other request´s in a front(from same scenario) are detained until the previous request will not be with 'Success 200 OK'
I am right?....if yes...is possible set someting like 'Allow to send waiting request´s' ?

Thank You
Regards Zdenek Chládek