How can I manage stock and cost for individual items sold from a set?

[KHC]

I have a problem in Stock management.

In my shop, some of the items are bought in sets ( 5 pieces per set or 6 pieces per set) and these sets comes in various sizes in one set.

Some customers want to do not want to buy the whole set. They want only one piece. So, I sold them separately. 
The problem I am facing now is how to remove this sold piece from POS software ( coz I put the set under one code) ? 
How to calculate cost of that sold piece ( coz the come in various sizes)?

Thanks

[hstb · Accepted solution]

You really should use an app that you can create product bundles in.

[hstb · Accepted solution]

You really should use an app that you can create product bundles in.

[KHC · Accepted solution]

Thanks for your information..

Can you explain to me how that kind of app works, please?