How can I use more than one argument with the calendar block?

Issue Summary

I'm using the user relationships module and i want to show a calendar block that only displays nodes created by a user with whom the current logged user have a relationship. I had no problem displaying nodes as unordered lists so I know it can be done with other output styles (to perform this task you have to use an argument and some filters that come with the user relationships module), but when I added the argument I required to the calendar view or even the filters I needed the calendar stopped displaying anything. The argument i need to apply just needs the current logged user to be provided as a default argument so I think it doesn't affect the URL. Is it possible to use more than one argument with calendars? If it is possible, how can i do it? Any hints to make this possible?