I am trying to set up standalone openMRS on multiple devices and I want the database used my the devices to be merged together, is there a program or a way to do this?
This is not a supported configuration for OpenMRS Standalone, which is provided for evaluation purposes only.
In theory you could use the enterprise OpenMRS/Platform installations with a single database over a network, but there are some scaling issues that have been open for discussion for some time now.
Others can provide more insight into those problems/challenges here in this topic. 