I already know how can do it that, it is very simple, (of course after a few day of deep thinking and search). Here is the solution.
In BuildConfig.groovy inside the inplace plugin where we need import the domain class from other inplace plugin we add next code,
grails.plugin.location.'common'="../sdl-common"
We add this code directly below
grails.project.test.reports.dir = "target/test-reports"
The import code before equals
grails.plugin.location.'common'
is the name use for import the plugin data(domain class, etc) and
"../sdl-common"
is the route to inplace plugin, and when we need to import the data in our classes, or controllers, we only need add
import common.*
in the part where we import hte packages.