separate handset from other three

[uniquer]

Housemates have an Ooma, but I am considering adding an Obi on the dsl line.  Will it wreck our internet bandwidth to have two systems on the dsl line? 

I have a handset from a set of four in the house (sharing Ooma for the moment).  Is it possible to associate the one handset with an Obi and leave the other handsets monitoring Ooma?

[RFord]

Housemates have an Ooma, but I am considering adding an Obi on the dsl line.  Will it wreck our internet bandwidth to have two systems on the dsl line?

No!  What is your DSL Line upload/download?

I have a handset from a set of four in the house (sharing Ooma for the moment).  Is it possible to associate the one handset with an Obi and leave the other handsets monitoring Ooma?

No!!  I'm assuming that all four handsets are associated with a cordless system paired with a single base unit, which is currently connected to the Ooma unit.