Add a Variable to JMeter Pre/Post Processor and Use it on If Controller

I am trying to run 5 Thread Groups.

1. CreateAssets (This thread group creates assets)
2. SearchAssets (This thread group searches for assets continuously created before till all get available)
3. UpdateAssets (This thread group updates the assets which created before)
4. SearchUpdatedAssets (This thread group searches for updated assets continuously till all get available)
5. DeleteAssets

How I wants this to work is,

• Run 1 and 2 Threads Parrallaly.
• Once 1 and 2 is done, Start 3 and 4 Threads Parralally.
• Once 3 and 4 is done, Run Thread 5.

So far what I thought was to add if controller into thread 3 and 4, set a flag on the top threads and set that flag true once thread 1 and 2 are done, and add that condition to if controller.

Really appreciate if anyone can help me with this.

Thanks in advance.