One ring group points to another ring group issue


I have FreePBX and Asterisk 1.2.18.

I set up one ring group A to call another ring group B in “Destination if no answer”.

Ring strategy for both groups is “ringall”.

One of the extensions in group A belongs to group B as well.

Group A has two extensions and they ring simultaneously for the specified amount of time.

After that all extensions from group B ring except for the extension that belongs to both group A and group B.

Is this a normal behavior ?

Thanks a lot for your replies!