Use of Common Areas when the possessions are one tenants

[Earl W.]

Long story short: I rented to three qualified but young tenants.  A boyfriend/girlfriend couple and the girlfriend's cousin. For whatever reason they had a falling out. I've been getting texts from both sides complaining about the other side. This is what I've done so far.

Two bedrooms, three tenants.  One couple and one single girl. Tenant A (The couple) has asked Tenant B (The single girl) to leave and find a new place. Tenant B feels as if she's being forced out of the common areas and "pushed out of the house".  Tenant B wants to stay and demands to have access to all of the common areas including to the furniture in the common areas.  I tell tenant A that Tenant B has rights to the common areas.  Tenant A proceeds to tell me that Tenant B is MORE than welcome to use the common area as long as she doesn't touch any of her stuff....BTW the couch, Remote, TV, all decorations, etc all belong to tenant A... Tenant B asks me how she's supposed to be allowed in the living room when she's not allowed to sit on the furniture or use the TV.

My questions are as follows:  (I live in Iowa)

1.) I feel like it doesn't matter who's TV/couch/dining room table is in the common area, as long as it's in a common area all tenants should have EQUAL rights to said furniture.  If Tenant A doesn't want Tenant B to use her couch/TV then she should move it to her bedroom. That's just my opinion.

Anyways, are there any legal guidelines or links that deal with this matter that I can send to my tenants for review?

2.) When does this legally even become my problem?  I don't want Tenant B to feel like she's being pushed into her bedroom, but is it even my issue if she feels like she's being "harassed" by the other tenants.   NOTE: I did not rent "rooms" to each tenant.  I rented to the house to them together.