And agreed. Rika doesn't belong to anybody. Except herself. And maybe
by the Law as stated by the Spice Girls in Line 4, Refrain 1 of Two Become One
'Tonight is the night when two become one'
IshiYoshi therefore is no longer 2 but 1...
and so, IshiYoshi is part of her... IshiYoshi is part her...
same with Yossui...
therefore
Rika belongs to Rika = Rika belongs to IshiYoshi = Rika belongs to Yossui