How to supress the very next event of stream A whenever stream B fires

Question

I want to stop stream A for exactly one notification whenever stream B fires. Both streams will stay online and won't ever complete.

A: o--o--o--o--o--o--o--o--o  
B: --o-----o--------o-------  
R: o-----o-----o--o-----o--o  

or

A: o--o--o--o--o--o--o--o--o  
B: -oo----oo-------oo-------  
R: o-----o-----o--o-----o--o