Include fully-fledged project as subproject

I have the following problem: there is project with its own buildscript section:

buildscript {
    repositories {
    dependencies {
        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlinVersion"

when i include it as a sub-project into the other one (also having similar buildscript section) i get following error:

* What went wrong: A problem occurred evaluating project ':blablabla'.
> Cannot change dependencies of configuration ':blablabla:classpath' after it has been resolved.

This buildscript is mandatory for both of them since i need to get 2 scenarios working:

  1. When both of them could be built independently
  2. When blablabla is treated as a sub-project of the first one.

So, the question is how can i override (or disable) buildscript section of the project being included one?