Is the data actually related? If so, then create the relationship. You can do this two ways:
1. With the database window showing, click the Relationships button and link the fields. You won't be able to enforce referential integrity since it is SQL data, but the indexes will work.
And / Or
2. Create/modify the joins in the Query designer view. You can choose any of the different join types.
If there is really no relationship with any of the data, then either you don't want it related, or you are missing a junction table. You can create the junction table on either the SQL server, or in Access. I have an Access front end that links a SQL server database and an Access database with relationships in the front end this way.
Does this help?